附近居民区的雨燕巢区，回巢飞鸣

nesting

bird-seen:yes

playback-used:no

bird-seen:yes

playback-used:no

bird-seen:yes

playback-used:no

Dozens of birds flying outside 9th floor of hotel window.

bird-seen:yes

calling while sitting on nest

bird-seen:yes

playback-used:no

Dozens of birds flying outside 9th floor of hotel window.

bird-seen:yes

various calls at a large colony given by birds inside the nests and flying around

calling while sitting on nest

bird-seen:yes

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About 100 birds foraging over commercial fish ponds. Normalised, 12dB HP filter at 1500Hz.

bird-seen:yes

playback-used:no

bird-seen:yes

playback-used:no

I observed ~ 100 House Swift nesting under an overhead bridge/road in the city early in the morning. The adults were actively feeding juveniles and were very vocally active around nests with thrills and screams. The thrills are a done communally with many birds singing out together, gathering into a crescendo and down again. When 30-50 birds do it together it can be quite loud under a large bridge. A composite recording made from 2 different recordings is here. I am not able to clean the background sounds (cars, occasional Starlings and dogs) as calls are made almost continually by some birds. The sonogram show wonderful these calls are – very high frequency and stacked in uniform layers of 3-4khz, spaced very regularly, packing 13-16 calls in a second. The rising and falling nature of the group calls is created by more bird joining and then withdrawing as a peak is reached.

bird-seen:yes

playback-used:no