I have been thinking about this with quite some concern. You beat me to it to ask, though Neil asked at COG meeting on Wednesday night. Apart from that I really
enjoy watching them. I’m sure Mike Tarburton has the best (national) data on this. Numbers are in decline over many years. I don’t recall ever being years of not seeing them from and usually many times through each summer from the mid 1970s until recently.
I suspect far more likely to be connected to habitat problems in Asia, Combined with poisoning of large components of insect stock throughout their migration route. Though I am of two minds. Insect poisoning has been going on for decades before this decline.
Also, though this is without context, swifts and swiftlets (different species) are still in big numbers in Philippines, even above metro Manila, although that is only my observations in recent years. I don’t know anything about history. But it shows they can
cope with dense urbanisation.
Philip
From: Canberrabirds [
On Behalf Of calyptorhynchus via Canberrabirds
Sent: Friday, 12 February, 2021 12:25 PM
To:
Subject: [Canberrabirds] occurrence of WTNT in La Nina years
No-one seems to have recorded White-throated Needletails this season (20-21) in the ACT. I'm wondering if this is connected with it being a La Nina season and there being fewer classic thunder storms for them to track.
I looked up my records and in 10-11 (the last la Nina?) I saw them in the ACT only at the very end of the season (in March). Hope we see them this season still.
Expecting to be corrected about the correlation between sightings and La Nina and when the previous La Ninas were....
--
