Wednesday, June 1, 2011
Lovely Interlude with Kirtland's Warbler
(transcript of today's For the Birds)
On Sunday of Memorial Day weekend, I spent a few hours in the company of some exceptional birds—Kirtland’s Warblers. I saw my first Kirtland’s Warblers in a jackpine forest on June 6, 1976, when the species, the rarest songbird in North America, numbered about 200 pairs. Kirtland’s Warblers nest on the ground among the grasses beneath a jackpine tree. The tree has to be large enough to provide real shelter while young enough to still have its bottom branches. Jackpine cones open in nature only when exposed to the heat of a fire, and when humans started moving into north-central Michigan and started putting out forest fires, the jackpine stands grew older and less appropriate for Kirtland’s Warblers without new jackpine stands to take their place. The species numbers dropped dangerously, so Kirtland’s Warbler was one of the first to be named an endangered species and to receive major protection and help under the Endangered Species Act. But for over a decade, the numbers didn’t increase very much, and actually dropped to only 187 pairs in the late 1980s. It took several years of management by fire and planting to get enough jackpine seedlings old enough for Kirtland’s Warblers to nest. Now the landscape is managed via replanting rotations to ensure consistent habitat year after year and decade after decade, and the Michigan population reached 1733 pairs in 2010. In recent years, Kirtland’s Warblers have also started breeding in Wisconsin and Ontario. The Michigan population actually dropped from an all-time high in 1791 in 2008 and 1826 in 2009. People don’t seem very concerned about the drop in 2010, because many are hoping the population has stabilized and would be expected to have some ups and downs, but censuses this year and next should let us know if this is true.
This year, my morning with Kirtland’s Warblers started out at 7 am at the Ramada Inn in Grayling, where we met with a U.S. Fish and Wildlife Service tour leader, sponsored by Michigan Audubon, and were shown a brief DVD presentation about the history of Kirtland’s Warbler management—a film I’ve seen several times now because I’ve been on this tour several times. We had a fairly large group—15 people and our tour leader. This size of a group is fairly intimidating to birds, but from the moment we stepped out of our cars on arriving in the right habitat, we could hear Kirtland’s Warblers singing. Their voices carry much further than most warbler songs, and by the time we’d gone 50 yards or so along a path through the jackpines, we could hear as many as five or six at a time.
Kirtland’s Warblers may nest on the ground under jackpines, but they sing from the branches of oak trees, which didn’t have many leaves yet, so it wasn’t hard to pick them out at a distance. The birds didn’t approach the path while our group was passing through, but after the tour, because our particular route wasn’t on one of the most vulnerable, protected areas, our tour leader said we could stay around if we did not step off the path and did not play recordings to lure the birds in.
Out of the 15 of us, I was the only one who stuck around—everyone had had satisfying views through spotting scopes, but I wanted more. So after everyone else had left, I returned to a spot on the path that seemed to be the border between two different territories. Sure enough, the neighboring males came close to the border on several occasions, allowing me to drink in their presence, watching the cool way they bob their tails, how they make a soft “chup” note while browsing for insects through the branches of jackpines, and respond to each other’s songs. I was in heaven. I stuck around until the 11:00 tour arrived, and then headed home, driving the long distance with a smile on my face and some fairly decent photos on my camera’s memory card. A morning spent with Kirtland’s Warblers is a happy morning indeed.
Posted by Laura Erickson at 8:41 AM