Date: 7/9/18 3:13 pm From: DAVID A LEATHERMAN <daleatherman...> Subject: Re: [cobirds] Shocking Saga at Sand Dunes
Interesting saga. The snake involved is most likely the western terrestrial garter snake, which is highly variable in pattern but is usually fairly plain brown. Of course many snakes eat birds and many climb trees to find them, especially nesting situations with eggs and nestlings. I would agree with Chuck that rat snakes and bull snakes (aka gopher) are common tree climbers. The pink coachwhips in the southeastern part of the state have startled me more once going up or down trees with amazing speed. Rattlesnakes get ground-nesting birds on the Pawnee. Certainly snakes can open wide, certainly the real bulk of birds is less than meets the eye when their feathers are fluffed, certainly nestlings have more pliable bones than older birds. Snakes can swallow large objects by stretching bones only joined by ligaments (I.e., not truly fused), so it is not a true "dislocation". Achieving an angle of 150 degrees is possible in some species.
Thank you, John, for bringing this rarely observed event and even rarer documentation to us.
The snake may have detected the nest in the tree before climbing, but more likely, it was just systematically hunting. In New Mexico many years ago I watched a coachwhip systematically cruising cholla cactuses presumably for nests. Despite the thorns, the snake was able to navigate up and down the chollas rather quickly.
During the second Colorado Breeding Bird Atlas, at Riverside Park in Fort Morgan I watched a largish gopher snake hunting nests among cattails. The snake was swimming in shallow water while adult Red-winged Blackbirds followed its route scolding all the way. Periodically, the snake climbed among the cattails to check a nest. I couldn’t determine whether it was successful. Some of the nests may have been empty.
I don’t know if garter snakes can unhinge their jaws to swallow large prey, but I believe some snakes do. In that vein, in New Mexico I once watched a gopher snake on an American Coot nest. The snake was swallowing the coot eggs. It would open its mouth to encompass an egg. It slowly moved the egg into its throat. I could watch the egg move along the snake’s body until the reptile gave a slight twist, and the egg slowly elongated. The snake then engulfed the next egg.
We now and then witness Darwin’s struggle for survival.
Yesterday some friends and I saw a shocking sight that I will not soon forget. I was hiking and birding at the Great Sand Dunes with some friends when we spotted bird activity at eye level in an aspen tree on the side of the trail 15 feet ahead. Flitting around the tree was a pair of alarmed Dusky Flycatchers. Soon, we spotted a small nest in the tree, about 4 feet up, with something odd sticking out of the nest. My friend said “It’s a snake!” Sure enough there was a 14 inch Western Garter Snake coiled around the nest and in its mouth was one of the three nestlings! What a shocking sight to see! It was quite disturbing to watch but then again, this goes on all the time in nature, and is rarely witnessed. We had to swallow hard, and watch the drama unfold. The snake stayed on the nest for a good 20 minutes and continued to grapple with the nestling which was long since deceased. The bird seemed so much bigger than this small snake could handle. We left the scene after watching this disturbing yet amazing event and headed up the Mosca Pass Trail.
Upon our return 45 minutes later, we saw the snake at the base of the tree with the bird nearly devoured. We left the scene under the mixed emotions of grief, sadness and amazement all chaotically working inside us as we strolled down the trail to the vehicle.
The event sparked a number of questions. First, I never knew Western Garter Snakes could climb a tree so well and skillfully. I had always pictured them as ground-hunting predators, slinking through the grasses and brush. To see one in a tree definitely shattered my long-held belief.
Secondly, how did the snake know there was food in that direction? Was it a keen sense of smell? Or was it the sound of chirping babies on the nest? I am not exactly sure.
Thirdly, the snake was not large, being about 14 inches in length…not big as garter snakes go. But this snake successfully devoured the chick which was the size of a ping pong ball! It did take considerable time for the act to be completed, but I never knew snakes had such an extreme ability to accomplish such a feat.