Fall songbird migration is already winding down at the Lesser Slave Lake Bird Observatory. Big waves of most of our warbler species have come and gone. Yet the true vanguards of fall, such as Snow Goose, American Pipit, or White-crowned Sparrow have yet to arrive. Oddly, there were three very late-season families at the station this week from rather different species: Least Flycatcher, Swainson’s Thrush, and Red-eyed Vireo.
We have again been taking tail samples from a small subset of birds in collaboration with the Canadian Migration Monitoring Network (CMMN) to reveal important migratory connectivity and genetics of Canada-wide populations. This week we collected our first sample from a Palm Warbler. Palm Warblers breed east of the Rocky Mountains in the northern Boreal Forest and only migrate down to around Florida. Since they do not have far to go, they are one of our last warblers to move through.
Above: This Palm Warbler had two of it’s tail feathers taken for conservation research on Monday explaining the gap in the middle of the tail.
Tail samples can hint where a bird came from since atoms are made of electron, protons, and neutrons. While an element’s atoms must have the same number of electrons and protons, they can have a different number of neutrons since they are neutral. These atoms are called isotopes. For various elements, such as carbon, nitrogen, and hydrogen, certain isotopes are more common in some areas of Canada than others.
As plants grow, they take these isotopes up into their tissues, which are eaten by bugs, which are eaten by songbirds. Since baby birds grow their tails on the nest and shortly after fledging and adult birds replace all their feathers before their fall migration, isotopes in a tail feather indicate roughly where that bird spent its summer.
This is the fourth year we have sampled tail feathers for various projects. In 2022-24, we collected samples from flycatchers for an Environment and Climate Change Canada (ECCC) study on the impacts of industrial pollution on their declining populations, and for another project investigating the trade offs of nesting in nutrient-rich, but also contaminant-rich wetlands. As a shining example of the collaborative nature of avian studies, not only are we using our resources to collect samples for ECCC and CMMN, but they are also sharing their results with each other to minimize duplication of efforts, thus stressing fewer birds, and to stretch scarce funds for lab work as far as possible.
Above: In addition to banding the bird as we normally would, we hope to pluck two feathers from up to 40 birds this fall for isotope analysis.
The two tail feathers plucked from a small sample of captured birds are shipped off to Saskatoon for sequencing. Plucking does not impair the bird’s flight and regrowth of these feathers begins almost immediately. If we were to cut the feathers, we would not be able to collect a blood sample that is present at the tip of a plucked feather, and the feather would not regrow until the bird would have naturally moulted it out. Sampling is fast and hardly impacts the bird, but leads to a big impact on our understanding of their populations critical for sound conservation action.
By Robyn Perkins, LSLBO Bander-in-Charge
