(Transcript of today's For the Birds)
After an unprecedented mild winter and an unprecedented early spring, hummingbird sightings in the southern and central states are proliferating, as the tiny birds are being reported as much as 6 weeks ahead of normal. People checking out the map at hummingbirds.net have been seeing Ruby-throated Hummingbird reports as far north as the Twin Cities and three quarters of the way into Wisconsin already.
But checking the map at another website, ebird.org, shows hummingbirds no further than the northern border of Texas through central Arkansas and North Carolina. [Between recording this and capturing the map below, in the wee hours of March 27, a sighting was added in Indiana.]
So how are we supposed to know where hummingbirds really are, and when we should get our feeders out? Ebird is clearly the more authoritative site--every exceptionally early report for an area requires documentation. Hummingbirds.net is much less formal, with reports pretty much accepted on trust. I know that some of the early hummingbirds people have reported to me over the years have turned out to be moths or tiny songbirds such as warblers or kinglets, so every really early sighting has to be taken with a grain of salt.
On the other hand, Ruby-throated Hummingbirds are much more likely to be noticed in early migration by feeder watchers than by birders in the field, and a great many people reporting to hummingbirds.net specifically watch for that first hummingbird. Ebird attracts serious birders who seldom park themselves at the window watching for the first hummingbird--they’re out birding.
Ruby-throated Hummingbirds winter in Mexico and Central America. They normally start crossing the Gulf of Mexico in late February, which is pretty consistent with the data on hummingbirds.net--there weren’t many people reporting hummingbirds from down there to ebird until well into March, which makes me question whether they have enough reporters focused on hummingbirds for their map to be the more valid one.
Once hummingbirds cross the Gulf, they fatten up and tend to wander north with rising temperatures, which this year warmed up exceptionally early. Ruby-throated Hummingbird migration always follows that of Yellow-bellied Sapsuckers. Hummingbirds just don’t have many flowers to feed from when they first arrive in the north--they seem to reach my own yard a week or two before the cherry and apple blossoms open. What do they feed on when they first arrive? They depend on the running sap from sapsucker drill holes. According to ebird, there have been plenty of sapsucker sightings already well north of where hummingbirds.net shows ruby-throats. So the optimistic map may actually be correct.
The bottom line is, I just don’t know which map to believe. But you never know what’s going to happen in such an exceptional year, so I’m setting out a couple of hummingbird feeders this week. I probably won’t have any takers for another month, but you never know. I’d rather have my feeders out there and not get a hummingbird than live with the possibility that a very hungry hummingbird passed through and could find no food on Peabody Street. But whenever that first one arrives, I’m going to go straight to my computer and report it to ebird.