Crossbill Alarm Calls Alarm Calls Alarm calls are used by crossbills when predators are near. Predators include hawks and gangs of crows or jays. These are Type1 alarm calls. These special calls are toop -like in overall structure. A noisy flock of crossbills becomes hushed when one bird begins a series of alarm calls.
Birds become less mobilized and scan the air.
I have had caged crossbills give this call while they were traveling in the back of a covered pickup truck going 50 mph. If I would search out the windows, I usually found a large bird nearby, such as a flying hawk or a kestrel on a wire. Workers might hold tape recorders near birds while they are banded and measured. These calls are diagnostically different among the various crossbill species.