Arctic fox in summer fur
Arctic foxes preyed mostly on eggs when foraging among nesting geese and most of these eggs were cached for later use (83% were cached, 3% were eaten, 1% were lost, and 13% had unknown fate). From 1996 to 1998, foxes took 681 eggs, 24 geese, 10 lemmings, and 18 unknown objects. In addition to acquiering new foods, foxes also took foods from old caches (all foods from old caches were eggs). Acquiering of eggs from old caches was especially frequent in 1997 and 1998 when fox densities were higher than in 1996. Most geese taken by foxes were scavenged (20 of 24 geese taken were scavenging from dead geese), but we observed 4 separate cases of foxes killing adult geese. See Samelius and Lee (1998) and Samelius and Alisauskas (2000) for more detail (see Publications for complete references).
Arctic fox feeding on a snow goose
Nest attendance by geese was an important factor affecting whether geese lost eggs to predation by arctic foxes in both years that this study was performed (1996 and 1997). Higher egg loss of unattended nests and nests with only the female present resulted from a combination of (1) these nests being attacked far more frequently than paired birds and (2) that they offered little or no resistance compared to nests where both geese were present. See Samelius and Alisauskas (2001) for more detail (see Publications for complete references).
Arctic fox taking egg from goose nest
Nesting success of geese varied considerably among years and increased with increasing distance to fox dens. The influence of distance to fox den was more important in areas with low nesting density than it was in areas with high nesting density. Distance from the edge of the colony and outbreaks of avian cholea, in contrast, had a relatively minor effect on nesting success of geese. However, a correlation between dead birds and nesting density suggested that cholera mortality was a cost of colonial nesting and that there was a trade-off between nesting in high densities with low rate of fox exposure but with increased risk of cholera mortality.
Arctic fox pup