I am curious about the increase in robin flocks over the past several years.
I seem to remember that many years ago, I started to see small clusters of
unhappy looking robins on the bare grass above the underground steam lines
on the NIH campus around mid-February. Lately, each year the robins have
been showing up earlier and earlier and in greater numbers. I'd see flocks
come in on Beach Drive in Kensington to eat the crabapples in February, then
in January; now I've seen them there working the trees just last week! Last
year they came in late November-early December and stripped all the berries
off the two huge hollies flanking our house, as well as the ligustrum
berries at which all other birds had turned up their noses (beaks?).

Someone once told me that the winter flocks of robins were young males that
didn't have established territories yet. I've also heard that robins are now
the preferred hosts of West Nile virus-carrying mosquitos, based on a study
where scientists did DNA fingerprinting on the blood inside the mosquitos.

Why are there so many more robins, so much earlier in the year? Why are we
not finding lots of dead robins infected with West Nile, as was the case
with crows and jays when it first hit the corvid population? Are robins more
resistant to the virus? Are there any articles or discussions among
ornithologists that have been published? Just curious...

Mary LaMarca
Silver Spring