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. (2002) Modern Applied Statistics with S-PLUS. Fourth 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)