Thursday, September 2, 2021

Interesting Acorn Woodpecker Research

Acorn Woodpecker

Last year, Storey published a book of mine, The Love Lives of Birds, in which we highlighted 35 species and their different approaches to acquiring a territory and mating.

Some species—swans, cranes, crows and many jays for example—famously mate for life and stay together throughout the year, whether they migrate away from their territory or not. Some, such as albatrosses, loons, and eagles, don’t maintain a year-round bond but return to the exact same territory each spring, ending up with the same mate year after year as long as that mate also returns.  

Many songbirds commit to a mate for a single season, but the following year are as likely to settle in with another bird as that former mate. Some, such as House Wrens, stick with a mate to raise one batch of babies but then both birds very often find another mate if they want to produce subsequent broods that same season. Some forge a temporary bond for just part of the nesting cycle. For example, Mallard drakes stay with hens after courtship only through the time the females build nests and lay their large clutches of one egg a day for a couple of weeks. When a female starts incubating those eggs and loses interest in sex, her mate is out of there. Grouse, turkeys, woodcocks, and hummingbirds separate the act of mating from nesting and raising young; males mate with as many females as they can attract, forming no discernible pair bond with any of them.

There seem to be almost as many mating and territory strategies as there are bird species, and so covering just 35 species barely scratched the surface—that’s less than 5 percent of the more than 700 species that breed in North America, and less than a third of one percent of the roughly 10,000 bird species in the world. I could have written huge chapters about a lot of other birds, and particularly felt bad leaving out one fascinating species, the Acorn Woodpecker. Several researchers I know, including ones I worked with at the Cornell Lab of Ornithology, focused years of research on this amazing bird.

Acorn Woodpecker

I saw my first on Mt. Lemmon in Arizona on 7 April 1982 (no photos), and even before I got a glimpse of the birds themselves, I was gobsmacked by what they had done—one entire side of a log cabin where we stayed was riddled with hundreds, maybe thousands, of holes, virtually every one stuffed with a single acorn. I knew from my reading that Acorn Woodpeckers made these granaries, but had no idea they could be so huge, storing so very many acorns.

Acorn Woodpecker tree

The granaries are constructed by family groups of a dozen or more individuals, who store the acorns communally, and cooperatively raise the young. Living up to their name and all the work involved in building, stuffing, and maintaining those granaries, Acorn Woodpeckers do eat a lot of acorns, especially in winter, but overall, their diet is surprisingly varied. They glean and dig out insects from trees as other woodpeckers do; catch flying insects on the wing; dig out sap wells to feed like sapsuckers; eat flower nectar; take small lizards, baby birds, and eggs; and eat some fruit and seeds. They also visit feeders for seeds, suet, and hummingbird nectar.

Acorn Woodpecker

We know from decades of long-term studies of marked birds that Acorn Woodpeckers have an unusual mating system called opportunistic polygynandry. Within a group, 1–8 males compete for matings with 1–4 females who all lay their eggs in the same nest cavity. The males and females share incubating duties. In addition to these core breeding individuals can be 1–10 non-breeding “helpers” that assist the breeders in feeding nestlings. As with many other birds, such as crows and Florida Scrub-Jays, in which one or more individuals help nesting pairs raise their young, helpers at Acorn Woodpecker nests tend to be offspring fledged by the group in prior years. Non-breeding Acorn Woodpecker helpers may be as old as 5 years old. Cohorts of males and cohorts of females tend to be related to one another—usually siblings—but the two cohorts in a flock are not related to each other. Yep—that’s one heck of a unique mating system.

Acorn Woodpecker

For many decades, long-term research projects studying birds like the Acorn Woodpecker involved marking individual banded birds with uniquely colored leg bands or wing tags and spending many hours in the field observing their activities. New high-tech equipment, from RFID tags to satellite transmitters of increasingly tinier sizes, are allowing researchers to get data on many more individual birds 24/7, even when no one on the research team is anywhere near. Newer, less expensive ways of testing DNA have taken the guesswork out of determining paternity and, in the case of Acorn Woodpeckers and other species in which multiple females share a nest, maternity as well. Now, thanks to two projects led by Sahas Barve of the Smithsonian National Museum of Natural History, one published last year in Current Biology and another published last month in Proceedings of the Society B, we know a lot more about the Acorn Woodpeckers’ unique mating system, and also about how territorial battles between flocks attract non-participating Acorn Woodpecker as spectators. 

It's long been assumed that for species in which the male and female parents both make fairly equal contributions to raising their young, monogamous pairs that defend a territory, not sharing resources with neighboring birds, are more successful than polygamous species in which males share their territory with other males. But the 2021 Smithsonian project found that that those male Acorn Woodpeckers that breed polygamously in duos or trios of males each fathered more offspring than males breeding alone with a single female. Females didn’t get the same benefit. Co-breeding duos of females produced the same number of offspring as the females that coupled up, but female trios left behind fewer offspring than either group.  

Acorn Woodpecker

Acorn Woodpeckers may provide an exceptional example of cooperation in their mate- and nest-sharing, but they have a violent, bloodthirsty, side, too, as research published last year by the same team led by Barve proved. A nesting group’s territory averages 15 acres with one or more granaries. Ownership is stable until there’s a death in the flock. If a breeding female dies, for example, coalitions of non-breeding “helper” females from other flocks will battle with the breeding and non-breeding females from the other flock, trying to take over from the homeowning females. Invading females may return day after day from their own territory. The term “battle” isn’t an exaggeration. Barve told a New York Times reporter, “We’ve seen birds with eyes gouged out, wings broken, bloody feathers and birds that fell to the ground fighting each other.”  

Thanks to the RFID chips which tirelessly record birds every time they appear near the RFID reader, we know that some tagged individuals fought for 10 hours at a stretch for four consecutive days. Although a great many birds in the vicinity have been tagged, one long-lasting battle ended up being won by an unmarked coalition of females.  

No one knows exactly how Acorn Woodpeckers get the word out, but soon after a death occurs, invaders arrive, and within an hour after the first blows, birds from other flocks arrive to watch. They may travel more than 2 miles and spend a full hour watching these battles. Spending so much time attending these battles just to observe must have some value—these birds would normally be spending those hours feeding young, searching out more acorns for their granaries, and defending their own territories to prevent the theft of acorns. Dr. Barve told the New York Times that studying other Acorn Woodpeckers must give them some sort of advantage. “They must immediately see all the big sibling coalitions in the area, gauge their body conditions and the quality of the territory they’re fighting over,” he said.  

Working out the evolutionary advantages for watching other birds fighting is tricky, and we can’t help but wonder whether the impulse for Acorn Woodpeckers to observe other flocks engaging in these fights is comparable to the impulse of people to spend a significant amount of time observing football, World Wide Wrestling matches, or the crazier reality TV shows. But I guess it’s nice to know that there's a counterpart to spectator sports in the world of birds. Maybe there really is nothing new under the sun.  

Acorn Woodpecker

Monday, August 30, 2021

Interesting Hummingbird Research

Ruby-throated Hummingbird 

My backyard is still buzzing with hummingbird activity, but I haven’t seen an adult male in two days, and numbers of adult females and young birds are starting to wane.   

The peak of hummingbird migration coincides with hurricane season, and as Ida bears down on the Gulf Coast precisely where our Ruby-throated Hummingbirds are collecting en route to Mexico, my anxiety is growing. I keep reminding myself that hummingbirds have been using this route for millennia, and even as I realize how climate change is changing everything, making storms, floods, and droughts on average both more frequent and more severe, these tiny little birds really are powerhouses. Many will succumb, but we oh-so-intelligent humans are supposed to take the long view, that the ones who do survive have the genetic makeup to make their own descendants more likely to survive these and even worse conditions. I try to remember that, but my binoculars focus on individuals, not populations.   

I never get to find out what becomes of the individual hummingbirds I interact with—the ones who let me photograph them, the ones who rest in the box elder twigs near my office window and give me so many splendid photo ops. Some hummingbirds over the years recognized me and knew how to catch my attention to fill the feeders. My favorite of all was a female Ruby-throat who would tap at my window to get my attention when wasps were giving her trouble. I’d crank open the window and lean out with my hand vacuum cleaner to suck up all the yellow jackets in and near the feeder while she hovered just a few inches away, trusting that I’d never turn that noisy machine on her. That was in 2004, before I was taking many photos. I often wondered if she had to deal with Hurricane Katrina. 

White-necked Jacobin

Fortunately for my mental health, a bit of fascinating news about a hummingbird research project , about a species that won't be affected by Ida, was just released, distracting me for a bit. It’s about a gorgeous tropical hummingbird, the White-necked Jacobin, which I’ve had the wonderful pleasure of seeing, over the years, in Costa Rica, Panama, Trinidad, Peru, and Ecuador. The adult males have a glittering brilliant blue head and breast, bright, iridescent green back and wings, and a flashy white nape and tail. Most adult females—about 80 percent—have much duller brownish green feathers. 

White-necked Jacobin

But oddly enough, juvenile jacobins of both sexes are brilliant like the males! And even more oddly, about 20 percent of adult females retain that male-like plumage throughout their lives. 

Scientists collecting museum specimens have long known that when they skinned hummingbirds of some species, a small number of specimens that appeared on the outside to be males had, on the inside, ovaries rather than testes. Why this was and how those odd female birds interacted with other hummingbirds was extremely puzzling but hadn’t been studied until scientists at the Cornell Lab of Ornithology and the Smithsonian Tropical Research Institute set to work. The lead scientist on this project, Jay Falk, made this his Ph.D. research for Cornell. 

In Panama, Falk captured 436 jacobins between 2015 to 2019, and recorded the plumage type of each bird and whether it was a juvenile or adult based on tiny corrugation marks on the bill, which are significantly more abundant on juveniles than adults. He took tiny blood samples to get DNA confirmation of each bird's sex, banded and affixed each with a tiny RFID chip, and released them. Two females originally captured as immatures bearing male-type plumage were recaptured in at least one subsequent year as adults with the female-type plumage. But three females originally captured as adults bearing male-type plumage and recaptured in subsequent years retained that male-type plumage, and all adult females originally captured with female-type plumage retained that same plumage in any recaptures. The authors concluded that shifts from juvenile, bright plumage to dull female-type plumage occurs only during the immature period. 

The researchers set out many feeders with RFID readers, where they placed taxidermy mounts of juvenile and adult jacobins of both sexes and both plumage-types., and they recorded how many approaches by the marked live jacobins to those stuffed mounts were sexual and how many were aggressive. 

White-necked Jacobin

As far as sexual encounters, males clearly preferred females in the drabber female-type plumage. But they also attacked them aggressively much more than they attacked adult males, immatures, or adult females bearing the male-type plumage. Yes, the 20 percent of adult females in male-type plumage were attacked much less than the 80 percent bearing female-type plumage. 

Hummingbirds don’t form pair bonds—females have all the nest-building, egg laying, incubation, and childcare responsibilities. Scientists have always attributed the extreme sexual dimorphism in hummingbirds—those brilliant feathers on males and duller feathers on females—to sexual selection. They assumed that males compete with other males for the brightest plumage to attract the most females, and females bear dull plumage as camouflage during their nesting activities, but apparently the reality is more complex. The researchers observed and video-recorded females in the male-type plumage nesting successfully, so even though the study showed that given a choice, males preferred to mate with females in dull plumage, females in bright plumage were still successful in reproducing. They may have lost a bit of an edge in attracting males, but they had a real advantage when feeding, particularly at very busy feeding stations, where the brighter females visited feeders both significantly more frequently and for longer durations than the duller females. So both plumage types have an advantage for adult females, and evolution has kept both types alive, just as in our American Robins, males that are predisposed to migrate early have an advantage in years with early springs, while those that migrate later have the advantage in years with late winter storms. 

A lot of the news media headlined the story emphasizing that these females in male-type plumage had found a strategy to dispense with sexual harassment. If only human females could find such a simple solution!

White-necked Jacobin

Tuesday, August 24, 2021

Identifying and Misidentifying Birds

Rufous Hummingbird in Wisconsin, August 2007

In my blogpost about out-of-range hummingbirds, I quoted Scott Weidensaul, who noted that the out-of-range birds that appear in the East usually arrive here well after our Ruby-throats have disappeared for the season. That’s one of those rules that is virtually always true but has exceptions. For example, on August 11, 2007, I saw and photographed a Rufous or Allen’s Hummingbird at a feeder in northern Wisconsin. The homeowner noticed the little thing because it stood out by its aggressive behavior— even by hummingbird standards, it was exceptionally bellicose in chasing everyone from the feeder, a notable characteristic of Rufous Hummingbirds. They’re even tinier than Ruby-throats but more pugnacious—sort of the chihuahuas of the bird world. 

Selasphorus sp.-- probably a Rufous Hummingbird

On August 14 this year, Steve Patterson posted on Facebook’s KAXE-KBXE Season Watch a photo of a backlit hummingbird. 

Photo copyright 2021 by Steve Patterson

He took it for a Ruby-throat, though he wondered a bit because the bird’s throat was more speckled than most Ruby-throats. When I saw the photo, I immediately focused on the spread tail. The outer three feathers, like a Ruby-throated female’s, were tipped with white, with a darker section above that; the rest of the tail appeared quite orangey or rufous. Also, the bird’s sides looked browner over a more extensive area than most Ruby-throats’ do. I was certain that it was a Rufous or a very similar but even rarer possibility, an Allen’s. When I told Steve, he sent another photo he'd taken of the same bird. The sides didn't seem as rusty as I'd have expected, but my preconceived notion kept me from looking too carefully.

Photo copyright 2021 by Steve Patterson

Steve, who generously and frequently contributes his photos and insights to that KAXE forum, gave me permission to share his photos on my blog. As I studied them, I suddenly realized my initial impression was wrong—the rufous color of the tail feathers was simply an artifact of the backlighting. When I started focusing on the central tail feathers, which lacked white tips (as they should for all three possibilities—Ruby-throat, Rufous, and Allen’s) I suddenly realized that those central tail feathers in Rufous and Allen’s are dark-tipped, which would have been clear in the photo despite the backlighting. 

Rufous Hummingbird
This real Rufous Hummingbird is in range, in New Mexico in July 2013. 

The fact that the rufous color extended all the way to the tips of those central tail feathers made it clear that rufous was not the true feather color. The bird really was what Steve originally thought, a Ruby-throat. Oops! I was wrong. 

Again, during the peak of migration, just about every hummingbird we’re ever going to see in the Upper Midwest will be a Ruby-throat. Giving them more attention just in case is still warranted, and sharing our sightings of outliers is important. But when we post sightings of rarities on eBird, a valuable tool for researchers as well as list-keeping birders, we will always be asked for documentation, which virtually always requires clear photographs. With active birds such as hummingbirds, those photos can be essential for accurately identifying the birds in the first place. 

If I’d seen but not photographed Steve’s bird in that lighting situation, I’d have submitted it as a Rufous or, more generically because of the even more remote chance of Allen’s, as a Selasphorus sp. Although eBird would have let me count it that way on my own private list, the sighting would probably have, quite rightfully, been rejected by the eBird reviewer for their scientific database despite my certainty that the bird had so much rufous coloring. Had I taken the photo and submitted that to eBird as a Rufous Hummingbird, the reviewer or a researcher down the line would have noticed the problem with the central tail feathers and, again, rejected the sighting. 

We birders can’t help but be embarrassed, even mortified, when we make a mistake. Some birders at all levels think eBird's requests for documentation are personal attacks on their birding skills. But the whole point of identifying birds is to, well, identify them. Accuracy is essential in such a geeky hobby, isn’t it? Our lifelists and other birding lists are meaningless if we don’t have enough humility to clear out erroneous IDs when we realize an error or don’t have enough information to absolutely confirm a sighting isn’t something else. Rather than focusing on hurt pride, good birders learn from their mistakes. By admitting errors publicly, those of us who write field guides and lead field trips can help others avoid those same mistakes. 

Double-credted Cormorant

I’ll never forget when a Yellow-billed Loon was sighted along Brighton Beach in Duluth in October 1987. I heard about it while I was counting at the Lakewood Pumping Station, and was told it was working its way up the shore. This was in the days before cell phones and text messaging, and the original sighting was a good 45 minutes before I heard about it, so I decided to pull over everywhere I could as I worked my way toward the beach. Three or four other very experienced birders were also arriving when I pulled into my very first stop—our group included some of the top birders in the state. We scanned the water and almost instantly spotted the bird—that low-slung loon shape and what appeared to be a solid yellow bill, subtly upturned.  

We were of course thrilled—this was only the second sighting ever of the species in Minnesota. We all got great spotting scope looks, and then something about it struck me, and I suddenly realized it wasn’t a loon at all, but an immature cormorant. Everyone looked again, and sure enough. And we all made it down to Brighton Beach where Kim Eckert still had a spotting scope pointed at the real Yellow-billed Loon. 

It was embarrassing of course, but a good lesson about self-delusion when you are expecting to see a good bird. It was also a good lesson in how swimming cormorants do have a loon-like silhouette, and that the way cormorants hold their head slightly uptilted can be a little similar to how Red-throated and Yellow-billed Loon bills are slightly angled upward. 

Even as I was figuring out how important this lesson would be in helping new birders with waterbird identification, the mortification was too much for the others, most of whom had been birding even longer than I had at the time. They swore us all to secrecy, to never ever divulge that we had made that egregious error. I couldn’t help but tell the story on myself many times over the years, but I never did mention who else was with me there. 

Misidentifying birds goes hand-in-hand with identifying them, especially when hoping for an occasional rarity. There’s no shame in making a mistake—the birds truly do not care what species we think they are. But being incapable of admitting a mistake—well, that IS a shame.   


Monday, August 23, 2021

Hummingbird Outliers

Rufous Hummingbird at feeder, November 2004

One of the first things we birders in the eastern half of the continent learn is that the only hummingbird that ranges here is the Ruby-throat. Like all good rules, this is true, but like most good rules, there are important exceptions. As August works its way into September, the hummingbirds at our feeders really are just about entirely Ruby-throats, and because that is true, few people scrutinize them just in case there’s an inconspicuous outlier among them. But the outliers may be more than curiosities and cool checks on our birding lists. If we keep track of them over the years, especially in the context of citizen science projects such as eBird, our records may help provide valuable insights into such environmental issues as climate change and tropical deforestation.

Over the years, I’ve seen a handful of non-Ruby-throated Hummingbirds in Minnesota and Wisconsin: an Anna’s Hummingbird in Grand Marais in November 1991 (a species normally found in the far West from Arizona and Baja California through Oregon, Washington, and sometimes along the Pacific Coast of Canada and southern Alaska), and a Calliope Hummingbird in the Twin Cities in December 1994 (this one doesn’t have as limited a western range, nesting in the Rockies, regularly migrating through Wyoming, Colorado, and New Mexico, and more birds now and then wandering east). I also saw a Mexican Violetear in La Crosse in October 1998 (a tropical species, but occasionally a stray individual turns up in the United States). No one seems to have worked out a pattern to the violetear's wandering, but some individuals may have a weird genetic mutation that sends them in the wrong direction. 

Some of these outlier hummingbirds do die while out of range, as all hummingbirds eventually do even within their range. No one knows if a significant number of them ever find their way back to their natural range, but it’s possible that in a future where their normal range no longer supports them due to fires, droughts, deforestation, or other issues, those with a wandering gene may be the ancestors of survivors in the murky future. A changing climate will change the ranges of a lot of wildlife, benefitting a few species even as it wipes out others.  

The western hummingbird that wanders east the most often is the Rufous Hummingbird. I’ve seen them in Minnesota and Wisconsin on a few occasions, including in my own backyard every day for over two weeks in November 2004 (when I took all the photos used on this blog post). 

Viola the Rufous Hummingbird

The brilliant naturalist and hummingbird-bander Scott Weidensaul was one of the first to suggest that Rufous Hummingbirds are almost certainly in the process of evolving a new migratory pattern and wintering range. On his website, he states:

Changes in the landscape, and the ever-warmer winters of the past century, may be combining to make the East and especially the Southeast perfectly hospitable to these birds. Those that survive and return to their breeding grounds are, in all likelihood, passing on their once-unfavorable genes to new generations. Banding studies in the East suggest the number of wintering hummingbirds is increasing dramatically, and that we may be seeing the rapid evolution of a new migratory route and wintering area for these birds.

Although most Eastern homeowners take down their hummingbird feeders when the last rubythroats depart in September, these western species don't usually appear until much later in the fall - October, November or even December in the latitude of Pennsylvania. For that reason, it's a good idea to leave at least one feeder up and filled through at least Thanksgiving, even if it freezes at night - and to contact a bander if you have a hummingbird in late autumn or winter.

These hummingbirds do not need to be "rescued," as they sometimes are by well-meaning but misguided people who think it is better to keep them in captivity, or ship them south. This is illegal as well as unwise. The hummingbirds are healthy and well-adapted to their new situation, and have already migrated thousands of miles to get there. Please enjoy them, but don't interfere.

Rufous Hummingbird at feeder, November 2004

Tuesday, August 17, 2021

Tiny Miracles

Ruby-throated Hummingbird at bee balm

The seasonality of life can be entirely different within just one single species, sometimes varying by age, sex, or both. 

Take Ruby-throated Hummingbirds. From the end of June through the first half of July, a lot of people up here were emailing me or complaining on Facebook about how few hummingbirds were coming to their feeders. That’s the time of our summer season when adult female hummingbirds are focused on raising young and searching for high-protein insects to feed them. They raise one or two broods each summer, each clutch of two eggs in a brand-new nest that the female built. 

Ruby-throated Hummingbird

After laying the eggs, she spends about two weeks incubating them, then three weeks feeding the nestlings by regurgitation, and then stays with the fledglings for another week or so. And most adult males, not focused on baby care but still interested in mating with females who may be starting second broods, spend their time closer to where the females are than at our feeders. On my corner of Peabody Street this year, one female must have been nesting in a tall tree in mine or my neighbor’s backyard—I saw her almost daily, sometimes several times each day, but always high in the trees, never near my feeders. The few times I got a glimpse at a male, he was up there, too. 

As early first broods of hummingbirds fledge, many mothers lead their offspring to natural food both for the chick’s sake and their own. They visit the colorful flowers we associate with hummingbirds, but even more often to the drabber flowers high up in shade trees and other inconspicuous feeding spots. 

Hummingbirds burn a lot of carbs in their day-to-day lives, and incubating eggs is even more energy-intensive, but producing those eggs requires protein, and the growing nestlings and fledglings, building body mass, muscle, and feathers, need even more protein. Locally native herbaceous flowers, shrubs, and trees provide both high-carb nectar and high-protein insects. When females start a second clutch, their newly independent first brood continues feeding mostly where their mother taught them for days or even weeks before they discover feeders. But some mothers do introduce their young to feeders. When two or three hummingbirds feed peacefully at a feeder without any chasing, that’s usually a mother showing her young a new food source.

Ruby-throated Hummingbird

Once adult females start incubating a second clutch of eggs or it’s too late in the summer to start a second brood, they lose interest in sex, which is when adult males lose interest in them. When no more interested females remain near a male’s territory, even as the child-rearing season continues for the females, adult males transition from their mating season to their bulking up, pre-migration season.

Ruby-throated Hummingbird

Those males enter their migration season weeks before adult females or young hummers. By late August it’s rare to see a hummingbird with a red throat. 

The depleted mothers take much longer than their mates to reach migratory condition. As fledglings reach full independence, they also focus on bulking up—the last chicks to fledge, here and further north, are usually the ones visiting our feeders into September. They know they must migrate. It’s not our feeders holding them north—they simply cannot head out until their bodies are in the best condition and at the right weight.  

Ruby-throated Hummingbird

This year’s drought, impacting both herbaceous plants and trees, may have affected nesting success, and it’s almost certain that poor air quality from so many fires has taken an even larger toll on birds than on humans—birds can’t retreat indoors with air filters when their lungs start hurting. That’s the sort of health situation that doesn’t outright kill birds or humans, but compromises health and can mean life or death in a physically demanding situation. 

Ruby-throated Hummingbird

Fall migration isn’t a single straightforward season for Ruby-throated Hummingbirds—first comes the moseying part when they head to the Gulf Coast, mostly by day, resting and feeding along the way as opportunities arise. 

The Gulf of Mexico represents a fork in the road, and they have two options. Some strike out directly over water to the Yucatán Peninsula, a minimum of 500 miles away if they started out at exactly the Mississippi Delta and if they arrive exactly at the tip of the Yucatán. The journey is usually significantly farther than that depending on where they take off and land and how much the wind throws them off course. No matter how long the journey, these birds take off after a big breakfast and fly every moment of the rest of that day, throughout that night, and well into the next day before they reach landfall to finally rest and eat again. Ruby-throats in the best physical condition to start with seem to be the ones who take this direct over-water route.

The ones moving along the coastal land route have a much longer journey, and not less treacherous—either way, all these tiny birds are making this difficult passage during the peak of hurricane season. Just thinking about that makes me terrified for them, but even the tiniest birds are far less likely to be consumed by fear than we lesser beings are. 

Ruby-throated Hummingbird

Our Ruby-throats don’t breed during their time in the tropics, but it’s hardly a vacation. They must compete for food with the dozens of hummingbird species already there, most of which are larger and already familiar with the landscape. And there are a host of tropical dangers such as bird-eating spiders, a host of small raptors, and large flycatchers. And some snakes lurk within the foliage of tropical plants to strike out at any bird that might approach the flowers. The first time I was in Costa Rica, I set up a microphone and recorder at a feeding station. When I returned, a few hummingbirds were chattering aggressively at the cord while moving in hovering flight along its length—they must have thought it was a snake, and I felt very guilty that my equipment had disturbed their day.  (You can hear the 10-minute recording of hummingbirds flying by, some cursing the microphone cord, here. I don't have a photo.)

Despite all the dangers to and fro and in between, every year sometime around Mother’s Day, hummingbirds reappear in my yard. Every single one of these birds that weighs only an eighth or a tenth of an ounce (you could mail at least 8 of them with a single postage stamp!) survived its long migration down to Mexico or Central America, the treacherous season in the tropics, and its long migration back here. Imagine that! And if that’s hard to believe, I can barely wrap my head around an even more incredible fact: there are four records of hummingbirds listed on the Patuxent Bird Banding Lab website who were caught, all alive and healthy, more than 8 years after first being banded. (All four of them were quickly released after recapture.) All four had been originally banded as an adult, so they were each a minimum of 9 years old when retrapped and released. Some or all may quite possibly have been even older than that!

Some people look up to the heavens in search of miracles. Me, I just direct my eyes to my hummingbird feeders.   

Ruby-throated Hummingbird

Monday, August 16, 2021

Dogged Birding after the Dog Days of Summer

Red-eyed Vireo
Red-eyed Vireos will be passing through from now into September.

It’s still hot out there, but the dog days of summer officially ended on August 11. The period from July 3 through then was when the Sun appeared in the same region of the sky as Sirius, nicknamed the Dog Star. Yep, technically, the dog days are defined celestially, not by how the hottest time of year makes even the peppiest dogs slow down. 

Muxy and Pip go for a walk!
Even when Muxy was five years younger, she needed a cooling neckerchief to negotiate warm days.

My little dog Pip doesn’t enjoy hot days, but she’s not as badly affected by heat as my daughter’s big bull terrier Muxy, who was always stressed by heat and now is getting old. When Katie and Michael tried taking her along on a slow, easy walk with their baby on a day in the low-80s with low humidity, they ended up calling us to come and pick up her in the car. Poor Muxy has clearly not noticed that the dog days have been over for several days—she’s still languishing. 

Like the dog days of summer, autumn is technically a celestially-defined period—the time between the autumnal equinox and the winter solstice which this year runs between September 22 and December 21. Birds pay far more attention to the night sky than Pip or Muxy or most people do—many nocturnal migrants use the pattern of the stars, and especially the location of Polaris in the sky, to orient and navigate toward their winter destination. But birds have no use whatsoever for human-imposed definitions of the seasons. Indeed, the concept of four seasons of almost exactly equal lengths would be preposterous to birds. In the avian world, the number of seasons in a year varies enormously by species. Sometimes even the age and sex of birds belonging to the same species determine their annual rhythms. 

Wilson's Phalarope
Wilson's Phalarope

By mid-July, shorebirds had already begun migrating south, especially some adult females. In the far north, where days around the Solstice are so very long but the warmish season is supposed to be so very short, bird pairs even out the division of labor between parents by giving the male most of the parental care duties so the female, her body depleted by egg production, can take some time off to recover. In some shorebird species such as phalaropes, the females don’t even incubate the eggs—it’s the males with the incubation patches. Right now, lots of shorebirds are passing through the Northland and even the central states. 

Rose (left) and Monty, Chicago's famous Piping Plovers. Rose had to produce a second clutch of four eggs this year after a skunk ate her first clutch. She was last seen before migrating on August 1. Monty's parental duties are over for the season, but as of August 13, he was still on the beach bulking up for his own migration. The chicks won't be leaving for at least a few days after he departs. They're still growing! Photo copyright 2021 by Susan Szeszol. All rights reserved.

But shorebirds are not the only birds on the move now. On August 13, I heard from James Stone, who for years has been keeping me up to date with interesting bird sightings in his neck of the woods around Northome. He writes:

Laura—the warblers and vireos started showing up in little packs about a week ago.  Big group today—lots or red-eyes and a mix of everything else, feeding on the lake insect hatches and having honeysuckle berries for dessert. I’m guessing they got north pretty early, and they’re a little early packing their bags. 

Yellow-bellied Flycatcher
Last week's Yellow-bellied Flycatcher wasn't in the Boreal forest--it was in my dogwoods. 

I’ve been seeing a few early migrants in my own backyard, too, including a small handful of warblers and Red-eyed Vireos. For some reason, one or two Yellow-bellied Flycatchers seem to show up in my backyard every spring and fall, snapping up insects in the back of my yard. My backyard habitat is completely different from the Yellow-bellied Flycatcher's breeding habitat, so most of my photos show them in typical backyard vegetation rather than in the boggy coniferous forest where books and radio birdwatchers like me tell people they belong. That’s the thing about migration—how could a Yellow-bellied Flycatcher possibly get from those boreal coniferous forests and peatlands to its wintering grounds in Mexico and Central America if it could only feed in boreal forest vegetation? It’s not like it can just pull out a communicator and tell Scotty to beam it directly to its wintering grounds. Yellow-bellied Flycatchers have one of the shortest stays in their breeding habitat of any of our Neotropical migrant songbirds, often arriving, nesting, raising young, and heading out of the northern forest in fewer than 70 days, which is why my backyard photos of them are all dated from late May and then August—they are mostly gone by Labor Day. 

Yellow-bellied Flycatcher
I photographed this Yellow-bellied Flycatcher on May 26, 2020, in my crabapple, a tree that would not be anywhere near where it would end up nesting. 

I’ve not seen any flycatchers in my birdbaths, nor vireos, but thrushes, flickers, Pileated Woodpeckers, and even treetop warblers come down to birdbaths to drink. 

Blackburnian Warbler

During this infernal drought, my birdbaths will be more important than usual for migrating birds. And as James Stone notes, natural bodies of water, from lakes to creeks, provide lots of insect food and fruit trees provide carbs and vitamins, as well as other kinds of insects. The simplest way to enjoy the passing parade of fall birds in your neck of the woods, however those individual birds are defining their fall season, is to park yourself near a birdbath, fruiting trees or shrubs, or a shoreline and watch for movement. Keep looking up, too—nighthawks should start coursing through any day now, and a few hawks are already on the move. Frank Nicoletti even reported a Swallow-tailed Kite north of Duluth a few days ago. Migration is like a box of chocolates—you never know what you’re going to get, but it’s certain to be sweet.

Pileated Woodpecker at my birdbath

Thursday, August 5, 2021

Murky Vision

Young catbirds

One gloomy November back in the 80s, the sun came out just once, on my birthday as it happened. I remember how melancholy that month was, a gloom that didn’t just settle in—it got worse and worse as the month wore on. Somehow, we adjust to a certain amount of sunshine in a certain annual rhythm, and our spirits wilt when we get less. I don’t suffer from seasonal affective disorder, but this experience sure made it understandable to me. 

My cataract surgery just before the pandemic finally opened my eyes to the true blue of the sky, so I know what I’m missing right now. During this drought, we’ve had plenty of cloudless skies, but the murky haze enveloping the Northland has become as oppressive as that long-ago, dreary, overcast November, and this time it’s toxic—so much smoke from so many fires in Canadian provinces and Western states blowing in if there is any western or northern component to the wind direction. Last week, weather forecasters said our awful air quality would be dissipating by this past Tuesday, but no such luck. On Sunday, at least some of us Northlanders saw an unpredicted brilliant blue sky for the first time in weeks, but it was back to murky grayness before the sun even set. 

The air quality is frustrating for just about all of us, and outright dangerous for people with asthma and other health issues and for babies with their developing lungs. I brought my 11-month-old grandson outside for 10 minutes yesterday. I came in with a scratchy throat and burning eyes. Walter can’t say how he’s feeling, but he kept rubbing his eyes and nose for hours.

Young female cardinal

I spent a couple of hours outside on my own the previous couple of days, photographing nesting House Wrens and baby cardinals and catbirds, and watching my backyard baby chickadees, still hanging out with their parents but feeding themselves now. 

Chickadee siblings

Drought conditions are hard enough for nesting birds—one study on Song Sparrows concluded that they most successfully reared young in rainy seasons, and least successfully during droughts, not even taking into account how toxic air quality might exacerbate drought conditions. Baby birds cannot communicate discomfort to us the way human babies can, but their developing lungs must be at least as vulnerable as Walter’s. 

Young chickadee

I love looking at the Perseids every August, but this year, they’ll be very hard to see, hidden behind the murk. Stargazing is a lovely diversion for many humans, but detecting the stars is not just a fun hobby for birds—many nocturnal migrants find their way via celestial navigation. In these species, baby birds must learn the night sky, to see which star remains fixed, before they take off, and during migration, these young birds and adults all need to see the stars.  How will this horrible year affect them?

We humans can use air conditioners and air filters to make our indoor air safer than what it is outdoors, ironically contributing to the climate change that is the root cause of both the widespread extreme heat and drought and the extraordinary number of fires they brought on. We’ve had plenty of warning, for plenty of decades, that for plenty of reasons, both for the natural world itself and for our own self-protection, we must reduce our use of fossil fuels and commit to not just ending tropical deforestation but reversing it. 

We keep talking about our species being the smartest on the planet, but right now our intelligence is being tested on two fronts, and we’re failing badly on both. People rejecting the proven science behind vaccinations kept Covid spreading for critical extra months, allowing it to mutate into even more dangerous variants. And people rejecting the science that has long predicted global warming are still fighting efforts to at least slow the effects.  Of course we’ve always had droughts and fires and storms and disease, and always will. But our intelligence combined with our sense of community used to help us solve, and sometimes outright prevent, many dangers.  

Chickadees, just as invested in their personal survival as humans, find a much better balance between independence and community. I’m starting to wish the people who ostensibly live by a Constitution would pay closer attention to that Constitution’s underpinnings, which pretty much describe the way chickadees organize their social flocks. The Preamble reminds us that the whole point of our government is to "establish Justice, insure domestic Tranquility, provide for the common defense, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity." This past year we American humans reduced the life expectancy of our own population by a full year and a half. Birds, who suffer even more than we do from human greed, shortsightedness, and lack of community spirit, may not be as intelligent as we are by some measures, but they’re definitely a lot smarter. 

Statue of Liberty

Wednesday, July 21, 2021

Of Nighthawks and Kind People

Common Nighthawk

Yesterday, I got an email from someone named Dan who was in the middle of a nighthawk emergency. I virtually never give out my home phone number, but I made an exception because he sounded very nice and very anxious. And a few minutes later, my phone rang. 

Dan lives in Jackson, Wyoming, where he had hit a nighthawk with his car. It fell, wings outstretched, on the road. A vehicle was approaching from the opposite direction but simply straddled it, so Dan turned around to check the poor thing out. It couldn’t fly, but didn’t seem to be wounded, so he brought it home and placed it in a small safe enclosure. 

Not many rehabbers deal with nighthawks, and most of the ones that do handle only nestlings. This species is uniquely high maintenance because in the wild, once young birds fledge and for the rest of their lives, they eat only flying insects on the wing, their huge gaping mouth ideal for scarfing down moths, mayflies, winged ants, and other flying insects. A nighthawk flies into the insects at such a fast speed that the insects go down the opened throat without any effort at all. The nighthawk's vestigial tongue is just too tiny to get in the way. Its beak is tiny, too, and rather loosely attached to its huge mouth, so a nighthawk has no way of picking up food items, much less getting them to its throat to swallow.  When a nighthawk has even a minor injury that grounds it, it’s pretty much doomed to starvation. 

All baby songbirds and many other kinds of birds, including nighthawks, are fed by their parents, and in a rehab situation, they usually open their mouths readily to be fed by a rehabber. Adult birds usually can feed themselves as long as provided suitable food. Flycatchers and swallows usually take their meals on the wing but have no trouble picking up mealworms, crickets, and other insects when in captivity. Adult nighthawks simply cannot do that, and they also don’t have a clue that there is any other way of getting food in. When I’ve rehabbed them, it took time and patience to get them to open their mouths willingly—until then, I’d have to very gently tease open the mouth. And even then, with the food in their mouths, adults, especially males, had trouble swallowing it. Females are the ones who feed the young, so they still have working muscles in the back of the mouth and the throat which they use to regurgitate the food into their waiting babies. Adult males haven’t needed to swallow like that since they were chicks. For at least a couple of days and sometimes a week after they were eagerly opening their mouth to be fed, I’d still have to stroke their throat over and over to help them get the food down. 

Fred the Common Nighthawk

On top of this, nighthawks have fairly fragile wing and tail feathers but very short legs. In the wild, they can keep their feathers in good condition, but in captivity, the tips of those flight feathers often get frayed without protective sleeves over the tips. And care has to be taken to protect their feet—they can’t perch on normal bird perches, so care must be taken to keep whatever substrate they’re kept on clean, especially because at least once a day they produce a very liquid and caecal dropping which is quite messy. Rehab facilities are usually much too short-handed to be able to devote the time and attention, day after day, to that kind of high maintenance. 

Anyway, Dan in Wyoming had called the nearest rehab facility which said they could just hold it for observation for a couple of days and then would have to have it euthanized. Dan googled nighthawk care and came upon a long blog post I’d written about it in 2012, which is why he emailed me. 

Because this is nesting season, he was concerned about more than just this one nighthawk being lost if it was taking care of babies. Knowing only the females feed the young, I asked him if it was a male or a female, and told him he could tell by what color the throat was. He said it was brown, with some white on both sides. I focused on the brown and said it must be a female, but I should have realized that male nighthawks also have a brown throat—the white bib is not part of the upper throat area—so the bird was probably a male. But both of us thinking it was a female made us both even more concerned about what to do. 

He said the bird seemed a lot more perky now. Sometimes it was spreading its wings on the bottom of the enclosure, but when I asked, he said it was holding them symmetrically, wasn’t listing to one side, and both eyes seemed fine. 

Since the only realistic choices were to see if the bird could be released or to take it to the rehab center, he wondered if it would be worth driving back to the area where he’d hit it to let it go. It was 20 miles away, which meant a 40-mile round trip for nothing if the bird couldn’t take off, but if the bird was okay, he wanted it to have a chance to find its nest easily again. He was worried because he wasn’t sure of the exact spot, but said he could find it within five miles or so. I figured that should be plenty close enough for a bird that covers a lot of ground hunting. So that’s what he did.

Almost exactly an hour later, my phone rang again. Dan told me that when he let go of the bird, it fell on the ground, but he let it get its bearings and then prodded it gently a moment, and voila! It took off, circling higher and higher in the sky.  

I haven’t rehabbed birds in over 20 years now. Many of the birds I took in were hopeless, and it grew more and more painful watching yet another one die from massive internal injuries after a cat attack, or after suffering extensive neurological damage from lawn pesticides. It was thrilling to hear about a happy ending right when I’ve been so sad and scared about how rapidly climate-change-related weather patterns have accelerated and how rapidly the COVID-19 Delta variant has spread. Yes, this was just one nighthawk, not a population, and won’t even begin to reverse the downward trend the species has suffered in recent decades, and certainly won't help with any other problems either. But Dan’s going to such lengths to help it made a huge difference in this nighthawk’s life, and in the lives of its mate and young, and that is something worth celebrating.   

Fred the Common Nighthawk

Sunday, July 18, 2021

Of Heat, Rain, and Particles in the Air

Young chickadee

I’m writing this on July 18, 2021, at my place in Duluth, Minnesota. There’s not a cloud in the sky, but the sky isn’t blue—more of a murky brownish gray. I can’t smell smoke today but I could yesterday, making us reluctant to open our windows last night—it’s hard to sleep when the inside temperature is 80º F, but even harder to sleep when you think about your baby grandchild, his tiny lungs still developing, breathing in dangerous particulates. 

This year’s dry June and July are the worst northern Minnesota has experienced since the Dust Bowl. Exacerbating the situation is the smoke from fires associated with the heat and drought in Canada and the West. Here in Duluth, we’ve had air quality warnings for weeks now.

I’m taking this situation very personally because of Baby Walter, but he’s hardly the only baby out there, and hardly the only baby I’m personally concerned about. We human parents and grandparents can at least minimize our children’s exposure to dangerous outdoor conditions, but what can my backyard Blue Jays, chickadees, wrens, and robins do to minimize their own and their babies’ exposure to this ever-present smoke?  

Baby Blue Jay begging from parent

Last week, the smoke from those distant fires wasn’t the only source of particulates in Duluth’s air. The Minnesota Department of Agriculture sprayed parts of Duluth and outlying areas, including my neighborhood, for “gypsy” moths. These invasive, non-native moths have caused billions of dollars of damage to Eastern forests since the mid-1860s, when Étienne Léopold Trouvelotin, a French artist who had immigrated to Medford, Massachusetts, brought egg masses from Europe in hopes that he could breed a hardy silkworm by raising them in the forest behind his home. The first recorded defoliation by these moths in the United States was in 1889 of the street trees in Trouvelot's own neighborhood. The moths have also been brought in less intentionally—they arrived in New Jersey in 1920 on blue spruce trees imported from the Netherlands. Little by little the moth has worked its way west and south. 

Spraying for it in recent decades has mostly involved what’s called BtK, the variety of Bacillus thuringiensis that targets lepidopteran larvae. Apparently little or nothing else is harmed by it, but it is utterly indiscriminate in which moth and butterfly caterpillars it kills. 

Great Spangled Fritillary
Caterpillars of all moths and butterflies, including this Great Spangled Fritillary, 
are killed by BtK


The Minnesota Department of Agriculture is still using BtK here and there this year, including in St. Louis County, but the spraying this week in my neighborhood was a species-specific pheromone bound to a polymer matrix. Assuming the pheromone is as safe as it’s supposed to be, I’m still uneasy with polymer matrices—it's just more particulate matter mingling with the smoke until it settles on the ground, where it's supposed to draw male "gypsy" moths away from the females to reduce reproduction. The polymer matrix is ostensibly inert, just as plastic microbeads are, but how do we know that its accumulation in our water and soil won’t eventually be just as bad as other plastics? It’s not considered an “active ingredient,” so its effects on human or avian lungs before it settles on the ground haven’t been studied at all. All this to kill an invasive exotic pest that got here in the first place thanks to people. 

This year, even with the serious threat from these moths, the north woods seems in far more danger from new weather patterns. Many of our conifers and birches are in jeopardy from so many 90º days, not even counting the lack of rain. Foresters need to be planning for changes in species composition in the northern forest, because these warming trends are getting worse. 


Connecticut Warbler
This Connecticut Warbler was easy to photograph this June because the roadside ditch along the sphagnum moss-covered ground is usually knee-deep with water. This year it was distressingly dry.


Thinking about my family and backyard birds and northern trees is sad enough, but then I think about the children and birds living in the huge swath of land where the fires are burning. When fires are small, at least some and often most birds and other animals can escape, but the size and duration of fires has been growing in recent decades. During the Dust Bowl, when conditions were as bad as people then could imagine, we were not yet spreading pesticides over the landscape, invasive species hadn’t taken over so much of our forests, prairies, and other habitats, and many of the other ways we've been developing and degrading habitat now make it even harder for a landscape to recover after a drought, even without a fire. 

A half century ago, when I was in college, I learned about the serious threat of climate change, along with a huge host of other environmental dangers caused by burning fossil fuels: Power plants where coal or oil is burned release nitrogen oxides, sulfur dioxide, particulate matter, mercury, and carbon dioxide into the atmosphere along with small amounts of toxic metals such as arsenic, cadmium, chromium, and nickel, and we have to deal with horribly toxic oil pits and coal ash disposal sites, oil spills, and pipeline leaks—the list goes on and on. We knew with the gas crisis in the 70s that our dependence on fossil fuels was also an issue of national security. 

Oil companies have long understood the implications of climate change, but even as they started planning ways to exploit Arctic oil supplies as the icepack melts, they've suppressed public information about climate change and ridiculed people talking about it, taking rather the opposite tack of Margaret Mead, who said, “I was brought up to believe that the only thing worth doing was to add to the sum of accurate information in the world.” 

Think of the decades we’ve squandered doing so little to find clean alternatives! And now my baby grandson, and those baby chickadees I’ve so treasured this year, can’t play outside without breathing in toxic particulates. 

Yes, I’m bitter and my sense of despair is growing. But just yesterday, my friend Karen posted a poem by Wendell Berry that calmed my soul, at least for a moment. He wrote:

The Peace of Wild Things 

When despair for the world grows in me
and I wake in the night at the least sound
in fear of what my life and my children’s lives may be,
I go and lie down where the wood drake
rests in his beauty on the water, and the great heron feeds.
I come into the peace of wild things
who do not tax their lives with forethought
of grief. I come into the presence of still water.
And I feel above me the day-blind stars
waiting with their light. For a time
I rest in the grace of the world, and am free. 

Baby W