Who knew? Tape shows deer raiding birds’ nests
Springfield — Could blame placed on coyotes and foxes for robbing spring nests of quail and pheasants be shared by an animal we thought feasted only on grass, twigs and farm crops?
Video evidence suggests that there is definitely another egg and baby bird eater among us.
The white-tailed deer.
Footage of deer literally cleaning out bird nests was captured by Pam Pietz, a wildlife biologist with the U.S. Geological Survey. It was part of a study conducted several years ago, but discussion on her findings recently came to light because of recent video evidence of wild elk dining on sage grouse nests in the west.
As part of a USGS study on grassland birds, Pietz’s research team, working at the Northern Prairie Wildlife Research Center in North Dakota, set up miniature video cameras that ran 24 hours a day.
The team was surprised to find deer raided more nests than red foxes.
Curious as to whether or not deer would eat bird eggs, Pietz arranged camera surveillance at a captive deer research center where quail eggs were placed in a nest that was within reach of a deer.
“It munched them right up,” Pietz reported.
The over-arching study, which is now in focus due to social media, outdoors media and the USGS website, was conducted over a four-year period in the 1990s. The USGS monitored 132 bird nests with cameras. According to results of the study, predation occurred at 57 of the nests. What culprit invaded four the of nests could not be determined, but it was clear that deer raided four of the nests. One nest was predated by a red fox, one by a weasel and two by a badger. Another nest predator could only be identified as either a fox or coyote, Pietz noted.
On the USGS website, specific cases of the evidence caught by cameras are detailed. Case No. 1 took place at 2:15:43 a.m. when an adult Savannah sparrow flushed from a ground nest that contained two sparrow nestlings and two brown-headed cowbird nestlings that were about seven days old. At 02:15:54, a deer appeared at the nest for three seconds and removed one nestling from camera view. At 02:16:29, the deer removed a second nestling. The deer caught a third nestling outside the nest at 2:17:01. At 02:17:14, the deer returned to the nest and removed the fourth nestling.
At 02:17:30, the deer examined the empty nest for five seconds before leaving.
In separate video, deer were videotaped depredating four songbird nests in grassland habitats in southeastern and north-central North Dakota. Those deer were caught on camera two Savannah sparrows, two grasshopper sparrows, one clay-colored sparrow, one red-winged blackbird and three brown-headed cowbirds. The birds were removed quickly at night and left no evidence of predation, a USGS report explained.
“Although probably opportunistic, deer predations clearly were deliberate and likely are more common than generally believed,” the same USGS report stated.
A scientific or biological explanation?
Eggs and baby birds are packed with nutrients. And biologists believe deer have been taking from bird nests forever.
“Some of these animals really are omnivorous,” Pietz said, referring to the fact that deer, like humans, could feed both on animal and plant substances.
As far as anyone could tell, no one had documented deer preying on nests before, Pietz said, though she pointed out that a few years ago Canadian bird researchers reported deer eating songbirds right out of nets being used by the team to study the birds.
According to Natural History reports by DNR and the University of Illinois Extension, deer prefer to dine on tender shoots, twigs, and leaves of trees, shrubs, and other plants. In Illinois, farm crops and waste grain are an important part of the deer diet.
“Additionally, deer eat many kinds of vines, grasses, and the green basal leaves of many woodland plants. Acorns, crabapples, and other fruits of trees and shrubs are preferred foods,” the U of I Extension noted, adding that “in an urban environment, deer may damage plants in vegetable gardens or used in landscaping.”
As for the nest raiding, biologists say the behavior of deer is probably not much different from that of a human at a drive-through window: The deer are simply taking advantage of a quick and easy meal.