Identifying Predators and Fates of Grassland Passerine Nests Using Miniature
Video Cameras
Figures
 |
| Fig. 1. Estimated daily predation rates (±1 SE)
for ground and aboveground nests of grassland passerines with and without
cameras, during incubation and nestling stages, in Stutsman and Barnes
Counties, North Dakota, 1996-97. Numbers of nests and exposure days
for each group were as follows: camera-ground-incubation 15, 68.5; camera-ground-nestling
23, 152.0; camera-aboveground-incubation 15, 36.0; camera-aboveground-nestling
17, 105.5; non-camera-ground-incubation 78, 413.5; non-camera-ground-nestling
83, 552.0; non-camera-aboveground-incubation 162, 782.5; non-camera-aboveground-nestling
138, 788.0. |
 |
| Fig. 2. Digitized images captured from videotapes: (A)
Mouse (probably Peromyscus maniculatus) killing 5-day-old clay-colored
sparrow nestlings, (B) thirteen-lined ground squirrel killing adult
female chestnut-collared longspur at the nest (ground squirrel had already
removed 4 of 5 nestlings), (C) long-tailed weasel inspecting the camera
after depredating common yellowthroat nest, (D) muzzle of white-tailed
deer removing nestlings from Savannah sparrow nest (black mark on lower
mandible is diagnostic), (E) female brown-headed cowbird removing egg
from unattended western meadowlark nest (cowbird destroyed entire 5-egg
clutch), and (F) 2-day-old western meadowlark crawling back into nest
12 hr after is was displaced by the adult female when she flushed from
the nest during the night. |
