The latest results of Common Swift observations

Some of the reasons for the Common Swift’s well-known “swee-ree” call are now understood.

1) It identifies the sex of individual birds (females call at a higher pitch than males) (Kaiser). 

2) It establishes the territory of a colony (Tigges).

 Further results

In the Belgorod region Common swifts hunt at different heights at different times of the day. At noon they hunt between 40 - 50 m and in the late afternoon between 20 - 30 m (Bulyuk & Chernetsov). In Pavia the Common Swifts prefer to occupy nesting sites between 9 - 14 m high, the exposure is not a significant factor of the nest-hole selection (Colombo & Galeotti). In Berlin they spend most of their time in a specific colony territory (Tigges). In Tel Aviv some Swifts share one hole for access to their nests (Bear). In Holland they enter their nests at 70 km/h (v. Arkel). In Nîmes Swifts seem to be sensitive to noise: they breed better in the quiet backyard of a museum than in nests facing a noisy street (Gory). In Italy males take a smaller share in caring for young (Carere & Alleva). In Kronberg nestlings leave their nest for the first time at late dusk (Kaiser) and in Sweden young Swifts sometimes roost in trees (Holmgren). 

 (For sources see the bibliography; the paper from Allon Bear is in preparation.)