Texas Ratsnake (Elaphe obsoleta
lindheimeri) predation on Hummingbirds (Archilochus sp.)
On two occasions I have observed subadult snakes of
this species capture, constrict, and consume free-flying hummingbirds. The birds were
attracted to numerous sugar-water feeders placed 2.0-2.5 m above ground in a Mexican Ash (Accer
berlandieri) tree in the author's yard in rural Atascosa Co., Texas. Both incidents
involved snakes that were larger than hatchlings but <76 cm TL. Both snakes were in
slightly under-nourished condition as evidenced by a visible vertebral ridge.
The first incident occurred on 2 October 1993 at ca.
1000 h. The victim was an adult or juvenile Ruby-throated Hummingbird (Artochilus
colubri) as this species was in autumnal migration at the time and heavily utilizing
the feeders. The snake was ca. 4 m AGL and no closer than 2.5 m to the nearest feeder,
although birds were constantly perching briefly on random branches throughout the tree.
The snake maintained its grip on the slender (2 cm diam.) branch with the posterior half
of its body while dangling the anterior half below the limb as it constricted and
swallowed the bird. The event required less than five minutes.
The second incident occurred in the same tree at 1730
h on 14 May 1994 and involved an obviously different snake. The bird was an adult
Black-chinned Hummingbird (Artochilus alexandri), the common local breeding
species. In this case the snake was perched on a branch (4 cm diam.) that supported a
feeder. The snake's head was no more than 20 cm from the feeder hanging below the branch.
The bird was struck as it alighted on a feeder perch. This snake also allowed the anterior
portion of its body to dangle below the branch during the entire process of striking,
constriction, and swallowing.
It could not be determined whether the snakes were
attracted to the tree because of the abundance of hummingbird activity or whether their
successful feeding was the result of random movement. Both snakes were captured, cursorily
examined, and released at a distance of ca. 50 m from the tree. Neither was observed again
near the tree.
Although members of this species are notorious
aviphages, I am unaware of previous reports of subadults preying upon hummingbirds.
The photos to the left were
hastily shot on 35mm slide film using available light. Click on an image to
see a larger version.
UPDATE: A similar observation,
with better digital photos, has been posted on Gerald Keown's Southwest Center For Herpetological Research
website by Michael Weidner ("Western
Rat Snake Feeding on a Hummingbird"). This, as well as similar anecdotes I
have received from other birders and herpers, indicate that juvenile ratsnakes are
especially likely to indulge in this behavior wherever the presence of feeders results in
a high concentration of hummers. The Sonoran Mountain Kingsnake (Lampropeltis
pyromelana) has also recently been documented to seek out hummingbird nests for
predation (LINK).
