Wednesday, April 18, 2007

Juncos on the Move

On the Wisconsin Birding Network, one birder observed:

"After hosting around 14 Juncos for the past two weeks, we are suddenly Junco-less following last nights movement. The yard seems strangely devoid of life without the constant trilling and chasing. Hopefully someone besides Cowbirds will soon fill the gap."

While another responded:

"Funny, I've still got Juncos here. There are 3 on my tray feeder as I type."

It's very doubtful that juncos I observed in my backyard over the past several days were the same ones that over wintered from late fall to late winter, and perhaps early spring. During suitable migration conditions this spring, there have been peaks and dips of junco numbers in my yard.

On Monday evening, my backyard was completely devoid of juncos – no evening feeding - and that night there was substantial migration. The following morning, instead of 40 to 50 juncos that have been in my backyard for the past several days, there were only 3. However, also yesterday morning there was a group of around 50 juncos near Parisi Park adjacent to the Pheasant Branch stream corridor (south of Waunakee).

The obvious answer is that they don't all leave at once (see the map below) and there are still juncos to our south that will be moving through as migration continues. As these flocks proceed, some of us may continue to see juncos in our backyards, while some of us might not. So, it isn't strange that some people report departures while others report arrivals, or what may appear to be minor changes in junco numbers. Chances are, though, during this time of year, we're not necessarily observing the same flocks of juncos day to day in our backyards. They're on the move!

Dark-eyed Junco range map

All images © 2007 Mike McDowell

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