Hi Tweets,

Mike Donahue writes:

>Michael Price stated in his message on hummingbird feeders "Since
>the virtually non-migratory Anna's Hummingbirds cannot survive the average
>northern Cascadian winter without feeder help...."
>
>I've been curious about this, since I can't imagine that these birds are
>surviving without feeders, but I've found hummingbirds in the dead of
>winter that were in an area AT LEAST 1/4 mile from the nearest feeder.
>(And that's assuming that one of the nearest houses had a feeder.)

The two observations are not contradictory, Mike. This far N (southern BC),
Anna's tend to be located on S-facing slopes with N-S ravines. In winter
here, it generally remains warm enough for insect life to continue
throughout the winter. When it does get cold, it's usually during periods of
arctic high pressure, usually with clear skies and bright sun. At midday,
the ravines are heat-traps, becoming small warm microhabitats with active
insect life and even some blooms. The Anna's forage in these. They use the
feeders for water and energy. I'm not sure how far they'll go from the
feeder to forage but up to a kilometer (0.6 mi) doesn't seem unreasonable.
Anyone know for sure?

>I've observed these birds consistently in these areas over the winter, so
>I know that the birds were not just passing though where I'd observed
>them; that this area was part of their regular home range. I think birds
>that ARE centered around feeders are biasing us towards the idea that they
>NEED them to survive.

In Vancouver BC, in winter, there are no Anna's where there are no feeders
with forage areas fairly close by. And they are a relatively-recent (1940's
and 50's) addition to the BC avifauna. Someone else would know for sure, but
I think they're fairly recent in WA as well, no? Seems to me that as late as
the 1930's they were rare N of northern California, but moved N in the
1940's as people established more gardens and simultaneously began
hummingbird feeding.

>I do believe that feeders are definately helping the population survive
>our winters, particularly when we have a more severe one. However, I'm
>not convinced that if everyone took their feeders
>down all at once that all the Anna's would die.

Well, there's one way to test the idea, though it might be terminal for the
Anna's. Better than that, can anyone think of where the Anna's limit of
survival without feeders might be nowadays?

Michael Price The Sleep of Reason Gives Birth to Monsters
Vancouver BC Canada -Goya
mprice at mindlink.net