Impact of habitat fragmentation on activity and hunting behavior in the tawny owl, Strix aluco

I examined the effect of woodland fragmentation on activity and hunting behavior in the tawny owl. I made three predictions on the effect of fragmentation, two of which were upheld and one rejected. Over 2 years, 24 owls were radio tracked in the nonbreeding season. Eight of these were in continuous woodland and the rest in highly fragmented woodland. For each owl, I recorded data on small mammal availability, diet, home range size, perch time, and interperch distance. In accordance with the first two predictions, owls in fragmented woodlands had longer interperch distances and perch times, but contrary to the third prediction, perch times were positively correlated with small mammal density. This was thought to be due to owls altering their hunting to other prey types when small mammals were scarce. Within fragmented woodlands, perch times were the same between the sexes, but males had slightly greater interperch distances than females. Male owls in fragmented woods flew 40% further per hour than males in continuous woodland. For data throughout the night, food availability and area of trees in home range accounted for 65% of the variation in perch times. For data before 2200 h, area of trees alone accounted for the same amount of variation. The data suggest that habitat fragmentation, particularly through reducing woodland area, can greatly influence owl activity and hunting behavior.