Foraging Ecology of Bald Eagles

Knight and Skagen collected during a field study on the foraging behaviour of wintering Bald Eagles in Washington State, USA data concerning 160 attempts by one (pirating) Bald Eagle to steal a chum salmon from another (feeding) Bald Eagle.

eagles

Format

The eagles data frame has 8 rows and 5 columns.

y

Number of successful attempts.

n

Total number of attempts.

P

Size of pirating eagle (L = large, S = small).

A

Age of pirating eagle (I = immature, A = adult).

V

Size of victim eagle (L = large, S = small).

Source

Knight, R. L. and Skagen, S. K. (1988) Agonistic asymmetries and the foraging ecology of Bald Eagles. Ecology 69, 1188--1194.

References

Venables, W. N. and Ripley, B. D. (1999) Modern Applied Statistics with S-PLUS. Third Edition. Springer.

Examples

eagles.glm <- glm(cbind(y, n - y) ~ P*A + V, data = eagles,
                  family = binomial)
dropterm(eagles.glm)
#> Single term deletions
#> 
#> Model:
#> cbind(y, n - y) ~ P * A + V
#>        Df Deviance    AIC
#> <none>       0.333 23.073
#> V       1   53.737 74.478
#> P:A     1    6.956 27.696
prof <- profile(eagles.glm)
plot(prof)
pairs(prof)