Ma. Butler et Jj. Rotella, VALIDITY OF USING ARTIFICIAL NESTS TO ASSESS DUCK-NEST SUCCESS, The Journal of wildlife management, 62(1), 1998, pp. 163-171
Artificial nests have been used in numerous studies of nest success be
cause they can provide adequate sample sizes and be placed in accordan
ce with experimental designs. However, the critical assumption that a
strong linear relation exists between success of artificial and natura
l nests has rarely been tested. In 1993-94, we estimated nest success
for upland-nesting ducks across northern Montana using data for artifi
cial (n = 953) and natural (n = 1,318) nests. We collected data at 16
research sites that had a wide range of success for artificial (0.08-0
.80) and natural (0.23-0.80) nests. Our data from 2 habitat types and
2 years produced a weak but significant linear association between suc
cess of artificial and natural nests (r(2) = 0.20, regression slope =
0.47, P = 0.04, n = 16). Success of both nest types varied by habitat
and year. For nests in planted cover, slopes of regression equations p
redicting success of natural nests from success of artificial nests va
ried by year (P = 0.02; 1993: r(2) = 0.57, P = 0.04; 1994: r(2) = 0.87
, P = 0.01). In 1993-94, the amount of concealing cover at a research
site was related to success of artificial nests but not natural nests,
which may indicate that different types of predators were attracted t
o each nest type and used different methods to find each nest type (ol
faction vs. vision). Data from artificial nests could not be used to m
ake valid inferences about success of natural nests in different habit
ats or years.