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Re: bird feeding habits



On Thu, 13 Jan 2000 Chirp50@aol.com wrote:
> 
> I work in a Wild Birds Unlimited and had a customer in the store that asked 
> some very thought provoking questions.  My customer lives in a rural setting 
> of Virginia and has fed the birds for several years.  He has noticed that the 
> birds will come to the feeder in the
> morning and feed actively till around 10:30.  He says after that time he has 
> NO birds in his yard.  Then they appear again around 1:30 in the afternoon 
> and feed for about 2 more hours.  His question to me was “ Why do they leave 
> at the same times every day?

It depends strongly on the species of birds at his feeder. Hummingbirds 
often engage in a behavior called "traplining": they travel along a set 
path repeatedly, coming back to the same food sources at intervals of a 
couple of hours or so. This is because their food sources are present at 
specific, predictable locations, but can be depleted; the bird feeds, 
then moves on, returning when enough time has passed for the flowers to 
replenish their nectar. From the behavior of a few certain flocks of 
crossbills, it appears that seed-eating birds, or at least those that eat 
seeds from erratic, superabundant, spatially predictable sources, may 
also trapline. If crossbills do this with pine seeds, I'm willing to bet 
that frugivores like waxwings probably do as well, their food sources are 
very similar in pattern of occurrence. Insectivores such as warblers, 
woodpeckers, Brown Creeper, etc. often wait until the sun rises and the 
day warms up and they have light to hunt by before they start foraging. 
On colder days, insectivores might hang around feeders until 10:30, then 
move off to seek insects.

Hope this helps,

Josh



Joshua S. Rose
Duke University
Department of Zoology

jsr6@acpub.duke.edu
http://www.duke.edu/~jsr6/