Monday, March 16, 2009

More siskins than ever before!

Sometimes I’m surprised when I am looking for information about a species and find that the information apparently doesn’t exist. Such is the case with today’s pine siskins.

All winter long I’ve had 3 or 4, and perhaps as many as 5 pine siskins at my feeders. After a late arrival compared with other local feeders, the birds have appeared daily and often multiple times each day at my feeders. This weekend, I suddenly have 10 pine siskins. The siskins visit at least three times a day and likely more as even I don’t spend every waking moment in front of the feeders to keep track of them.

So, my question was simply, are these likely to be 10 new siskins or my regular 5 siskins plus 5 new arrivals? And what I’ve discovered is that the spring movements of these birds are apparently not well studied enough to even provide a reasonable guess to that question.

Because these birds are irruptive and only head south when food supplies in the north are lacking, studying spring movements of siskins here in the south is inherently problematic. I found no studies about when the birds are likely to head north again.

The only answers I can find are anecdotal. Spring movements back to the north are called "protracted," based on when they return to their breeding grounds, with no actual peak to their movements. In my area, anecdotal evidence suggests the birds could continue to eat pounds of seed here in Pennsylvania well into April.

So I don’t know how long these little beauties will continue to grace my feeders or for how much longer they will continue to eat a hole in my birdseed budget. The only thing I am really sure of is that whenever they do head north again, they will be as fat and happy as my seed can make them.

3 comments:

Lynne said...

I was wondering the same thing about the Redpolls at my feeders at home. All winter I've had 2-4 Redpolls but last week on the day BEFORE the weather warmed and the winds came around from the southeast I counted 100+ Redpolls in an absolute feeding frenzy!
Would the increased numbers be birds that have come ahead of the weather? Do the numbers increase as southern birds arrive adding to mine? Does the back edge of migration increase in numbers as it moves or do they all start north at the same time and remain spread out?
I've never noticed the numbers of Juncos increase before they leave. Just one day- they're gone.

Carolyn H said...

Lynne: great questions all. My suspicion is that the birds are moving north, one warm day at a time. Hawks migrate north on southery winds, why not finch and redpolls? And those southerly winds often come just ahead of a cold front (which ends up bringing NW winds). Birds don't like to move on a headwind, so when the winds turn, they don't move for a few days. Snow geese and tundra swans follow open water north, usually stopping at the last open water until the ice opens on the next lake or pond to the north.

you're right about the juncos, too. There's no staging or gathering. One day they are simply gone.

Carolyn h.

Cathy said...

Sadly, the squirrels got too bad at the feeder and it was taken down. Funny, there's not too much info on them.