Interpreting Evidence of Depredation of Duck Nests in the Prairie Pothole Region

Appendix B, Table 6

Table 6. Distribution of eggshells by distance intervals at duck nests depredated by the principal predators of duck nests in the Prairie Pothole Region, 1972-92.

				Eggshell (%) by distance intervals from nest
Predator	Nest type^a	No. nests	No. eggshells	≤20 cm^b	>20 cm - 1 m	>1 - 2 m	>2 - 3 m
Coyote	Artificial	59	129	23	52	16	9
Red fox	Artificial	152	1^c	0	0	0	0
	Natural	1	0	0	0	0	0
Raccoon	Artificial	28	144	64	32	3	1
Striped skunk	Artificial^d	30	151	72	25	3	1
American badger	Natural	61	173	43	46	9	2
Mink^e
Weasels^e,f
Franklin's ground squirrel	Artificial	15	35	43	26	29	3
Black-billed magpie	Artificial	24	23	65	4	27	4
American crow	Artificial	51	61	52	31	10	7
Gulls^g	Artificial	14	26	81	12	8	0

^a	All nests had ≥6 eggs when last visited by an investigator before nest was destroyed.
^b	Includes eggshells in nests.
^c	Only 1 eggshell was found at the nest and the distance interval was not recorded.
^d	Excludes eggs from 16 nests depredated by a striped skunk that had a den near the nests and exhibited unusual behavior by taking many eggs from the nest sites toward or to the den.
^e	No data available.
^f	Ermine and long-tailed weasel.
^g	Ring-billed gull and California gull.

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