Hi Paul,
Dave Willard at the Field Museum in Chicago has a long term data set
of bird collisions, including 30+ years at a convention center on the
lake. He sees a clear pattern that the strongest correlation with
collision is whether the building had lights on or not. He says the
effect is quite powerful and the convention center is only about 4 or
5 stories tall.
Not sure if he has looked at weather patterns or not.
I do know some folks working on mortality from wind turbines have
noted that moralities are often high when there are low lying clouds,
because presumably the birds are flying lower under these conditions
and are more likely to run into something.
Also, if you have many gulls or corvids near the building often that
could be why you don't find many birds. According to Dave, they know
well all of the "best" buildings for getting easy early morning snacks
during migration.....
Hope your next cuckoo is alive one ;)
Chris Tonra
On Fri, Oct 21, 2011 at 1:16 PM, Paul Pisano <> wrote:
> This week I had the misfortune of finding 2 dead birds at the base of my
> office building - the U.S. DOT HQ in SE DC. The first was on Monday and
> was a NORTHERN PARULA. The second was this morning and was a
> YELLOW-BILLED CUCKOO. I think there were others lat night because I
> found an unusual feather (secondary?) of varying shades of brown, as
> well as a small mound of unidetifiable body feathers at two other spots.
> The secondary? could have been from the cuckoo, but was kind of far
> from the rest of the remains. Actually, the "remains" only consisted of
> a head, so clearly other factors are at play here. I'm surprised that I
> found both of them this week as: 1) it's getting late in the season so
> the number of migrants at all is going down, and 2) these are the first
> I've ever found here. Why I haven't found others earlier in the season
> is unclear to me (though might have something to do with the fact that I
> drive a few days a week, which doesn't have me walking along this
> stretch of the building - except this week when I took metro 4 of the 5
> days).
>
> Has anyone ever recorded a pattern between building strikes and the
> migration season? I'm sure that they've looked at weather, but Sunday
> night and Thursday night were very different in that respect (if I
> recall correctly). Just thinking out loud, perhaps later migrants are
> weaker, which means they might not fly as high (and hence more prone to
> hitting buildings)? I don't know, that's probably connecting dots that
> don't exist, but just has me wondering. Interestingly enough, this
> building is not even the highest in this area, and it not much higher
> than the building immediately across the street.
>
> BTW, this is my second dead cuckoo this fall though the other was a Ft.
> Dupont as was clearly not related to striking a building.
>
> Good birding,
> Paul Pisano
> Arlington, VA
>
>
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