Expect the unexpected!

On October 22, a Townsend’s Solitaire was seen very briefly at Cabot Head (https://www.allaboutbirds.org/guide/Townsends_Solitaire). This western species regularly strays into the eastern part of the continent, so it might be qualified as an expected unexpected species. Indeed, this Fall’s sighting is the sixth record at Cabot Head: the previous ones have all been in October, except one on April 15, 2016 (which was a nice way to start the Spring season!). The fifth record was a bird in our nets on October 10, 2022. None of these birds ever seem to linger, seen only briefly, sometimes with the fleetest of apparition: see them, blink, and they’re gone for good. It is always a thrill to see rare or vagrant birds, of course, even if this is definitely not the goal of the bird migration monitoring here. I am constantly amazed at the amount of luck needed to discover a rare bird: by definition, they are rare, of course, but some sightings are so fleeting that they seem to require an extreme set of lucky circumstances.  Vagrancy in birds, in and of itself, is a fascinating phenomenon, still poorly understood (although there is now a whole book devoted to the topic: ‘Vagrancy in Birds’ by Alexander Lees and James Gilroy. I have not, but am eager to read it.).

The past week was marked by absence, as fewer and fewer birds (and species) are present now: many species have had their sad LOF (Last of Fall) now, notably warblers. However, one never knows for sure until the very end of the season: One Orange-crowned Warbler was detected on October 21 and two Yellow-rumped Warblers on October 24. Blue Jay, Northern Flicker, American Crow are almost completely gone too. Hummingbirds, Vireos, and Flycatchers are long gone. Even Kinglets are being heard, seen, or banded in very small numbers now.

The most abundant bird of the past week is Pine Siskin, as anticipated in the Winter Finch Forecast (https://finchnetwork.org/winter-finch-forecast-2023-2024). We are seeing lots and lots of them, with daily totals reaching approximately 400 birds on several days. It is devilishly difficult to have a precise estimate of their numbers: they fly in tight and bouncy flocks, practically disappearing in cedars and other trees when they land to feed, and they move quite erratically all over Cabot Head. Pine Siskins like to fly high and feed on tree tops. But from time to time, they would scoop lower, which is why one net captured 51 of them (around noon on October 23): that was a great scoop! Eight more Pine Siskins were banded earlier on that day, as well as five more on October 12, reaching a season total of 64 birds so far, which is the second highest among Fall seasons. Pine Siskins have been banded in 14 of the previous 21 Fall seasons, usually in single-digit numbers. In Fall 2011, however, 170 Siskins were banded, 106 of them on one day, October 3, and 75 of the 106 in one big scoop in the same net (A1) as our current capture, also late in the morning. Back then, one of the Siskins already had a band on: it was banded only two months earlier at the Mackenzie Nature Observatory, in north-central British Columbia, a continent away (3,132 km, as the siskin flies… if the siskin was flying in a straight line). Remarkable!

On October 23, the day of the great Siskin scoop, we ended up banding 103 birds of 11 species (but no recaptures), finally breaking the 100-bird barrier for the season! (see previous post)

Other northern visitors were also detected this past week: a flock of 24 Snow Buntings and one Northern Shrike on the same day, October 23. Their arrival certainly marks the beginning of the end: another season will end once again on October 31. Let’s hope for more treats than tricks before it is finally over.