My sister and I were walking the family dog at
Mississippi State University on the afternoon of May 13. MSU is a fairly attractive campus, with a mix
of both old and relatively new buildings and a good many large shade trees. I am used to looking up, or at least directly
ahead, to find birds. Given
the fact that most birds spend a lot of time in trees and shrubs,
this makes sense. My sister, though,
drew my attention to something that I otherwise might not have noticed: a dead
bird on the sidewalk, in front of the campus library.
(Warning! The
images that follow may be disturbing to some.)
I immediately realized that the bird wasn’t a
run-of-the-mill urban species, such as a European Starling or a House
Sparrow. After I got a close look at it,
I identified it as a Louisiana Waterthrush, a species typically found near wooded streams, where it feeds on the insects and other prey that it manages to
catch in streams. It even builds its nest in or near a stream
bank. It is very much a riparian bird. As you might guess, the MSU main campus doesn’t
have much in the way of habitat for waterthrushes—the nearest bodies of water
are a couple of tiny experimental ponds.
There is Sand Creek, which runs north of campus and might provide
appropriate habitat, but it seems odd that the bird would have strayed
so far from breeding territory in that area.
Still, that is a possibility.
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| Louisiana Waterthrush -- note the white belly and sparse streaking. |
Maybe the bird was a recent migrant. If so, then it was a late one. According to Birds of Mississippi by William H. Turcotte and David L. Watts, Louisiana
Waterthrushes are very early spring migrants, usually arriving in Mississippi
in mid-March. Mid-May would be an
unusual time for an individual of this species to still be migrating, but
stranger things have occurred. I will probably
never know.
Despite their name, waterthrushes are actually warblers, not
thrushes. Their drab brown backs, pale
breasts with dark markings, and pink legs make them look somewhat like thrushes,
and their habit of foraging low to the ground is also a bit thrush-like, but that’s
about where the similarities end. Actually,
while waterthrushes do have markings on their underparts, those markings are
not spots, as you would see on most of the North American thrush species, but
streaks. Thrushes and waterthrushes
differ vocally, too, with waterthrush songs sounding high-pitched and “chirpy”
in the way that most wood-warbler songs do, and thrush songs having a more
ethereal, flutelike quality.
It’s worth noting that, while the Louisiana Waterthrushes typically
migrates early, its close relative, the Northern Waterthrush, is a late migrant. Northern Waterthrushes breed in Canada,
Alaska, and the upper portion of the lower 48 contiguous United States—farther north
than Louisiana Waterthrushes. They pass
through Mississippi from about mid-April through May 15, according to Birds of Mississippi. If the dead waterthrush at MSU had been a
Northern instead of a Louisiana, that would have made more sense to me. But the Louisiana Waterthrush has several characteristics that differentiate it from the Northern: the solid white throat (which is
usually finely spotted on the Northern), the straight line bordering the throat
(which is streakier on the Northern), the broad "eyebrow" (usually much narrower
on the Northern), and the sparser and broader streaks on the breast (usually
denser and finer on the Northern). I
also felt from the beginning that this bird’s bill was too large for a Northern Waterthrush, and
its underparts too white. It’s important
to be careful with the latter field mark, though, since there are some Northern
Waterthrushes that are very pale below, instead of the more common yellowish
color.
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| Another view of the waterthrush. The "eyebrow" flares out at the end. |
I don’t walk at MSU often enough to have found many
window-killed migratory birds (in fact, the waterthrush was the first one I’d
ever seen on campus), but my sister tells me that she has seen several during
the spring and fall. Unfortunately, this
isn’t at all an unusual occurrence throughout the United States. According to a recent scientific study (Loss
et al., 2014 [*ironic author name, don't you think?*]), collisions with buildings kill somewhere between 365 and 988
million birds each year in the U. S. The
reason for these collisions is that birds get fooled either by reflections—of the
sky or vegetation—in the windows, or by bright lights from inside the buildings. Interestingly (to me, at least), a majority
of these collisions are at low-rise buildings, rather than high-rises. In all likelihood, the high-rise deaths occur
mainly during the spring and fall, when birds are migrating, and collisions
with lower buildings are common year-round.
Also, mortality during fall migration seems to be higher than during spring
migration—possibly due to larger numbers of birds at that time, many of which are juveniles hatched during the previous summer. A great many juvenile birds do not survive
their first fall migration, so songbird populations are considerably winnowed
down by the time spring migration rolls around.
Some of that winnowing is normal and natural, and, as we’ve seen, some
of it is a result of man-made hazards along the migration routes. Regardless of whether the Louisiana
Waterthrush my sister and I found had been a summer resident or a recent
migrant, man-made structures had clearly caused its untimely end.
I decided to salvage the specimen for science. MSU has bird collections in both the Biology
and the Wildlife and Fisheries departments, and clean, intact bird specimens
like this are not always easy to come by.
My sister gave me an unused dog waste bag to put it in, and we
continued walking until we came upon another building-killed migratory bird: a
Veery. As I mentioned earlier,
waterthrushes are not actually thrushes.
However, Veeries are thrushes
(in the Turdidae family, Catharus genus), even though the word “thrush”
is nowhere in their name. This could be
pretty confusing for the uninitiated!
The Veery is named for its song, which supposedly sounds like “veer,
veer, veer, veer.” Well, to be fair, it’s
considerably more pleasant than that—a series of descending phrases that have a
fluty, echoing quality. Veeries are
truly transients in Mississippi. Although
some can be found nesting at very high elevations in the Great Smoky Mountains,
they’re generally not southerly breeders.
They’re also one of the harder-to-find thrushes in Mississippi, with the
Mississippi Ornithological Society listing them as uncommon transients.
 |
| Veery |
 |
| Another angle |
As you can see, the spots on a Veery’s breast are very pale
and blurry compared to those of most other thrushes (including Wood and Hermit
Thrushes). Veeries also have tawnier
upperparts than all other North American Catharus
thrushes. This tawny
coloration makes the cool gray of the flanks and belly stand out.
 |
| Vague, buffy spots and very pale undertail coverts |
I picked up this bird, too, and later got in touch with the
Wildlife and Fisheries Department to ask if they would take the specimens. I had given them a road-killed Eastern
Screech-Owl (which I had found in my neighborhood) many months before, so I fully
expected that they would be willing to take these building-killed Neotropical
migrants. They were. While it’s a shame that these two songbirds
died in such an unnatural way, the silver lining is that an educational
facility gained two relatively unusual specimens for study.
I suppose the lesson here for birders is to always be
observant, because you never know what oddities you might discover. I know that I will have to remember to keep a
look out for birds in front of buildings during the spring and fall from now on! But there’s probably a bigger takeaway in here for
everyone—birders and non-birders alike: We need to do more to reduce the number
of birds that are killed from collisions with buildings. Placing various grids and patterns on windows
to break up their reflections helps, as does turning off lights at night. A study by Chicago’s Field Museum demonstrated
just how effective turning off the lights can be: bird kills decreased by 83%! Obviously, it isn’t possible to
prevent all bird deaths, and people will
always need places to live and work, but maybe just a little more consideration
for the natural world could go a long way.
Sources and links:
- Loss, S. R., Will, T., Loss, S. S., and P. P. Marra. 2014.
Bird-building collisions in the United States: Estimates of annual
mortality and species vulnerability.
Condor 116(1):8-23. (http://www.bioone.org/doi/full/10.1650/CONDOR-13-090.1)
- Turcotte, William
H., and Watts, David L. 1999. Birds of Mississippi. Mississippi Department of
Wildlife, Fisheries and Parks. University Press of Mississippi,
Jackson.
