Unidentified Terns - Lake Victoria, Entebbe, Uganda (12.iii.2019) (1 Viewer)

[Cabintom]

Hi all! I'm new to birding, and as I live in DRCongo and frequently travel to Uganda & Kenya, there are apparently lots of species to see.

A little over a week ago I was down in Entebbe, Uganda where, among other birds, I snapped a few pictures of this flock of unidentified terns.

https://download.ams.birds.cornell.edu/api/v1/asset/146813731/1800

https://download.ams.birds.cornell.edu/api/v1/asset/146813701/1800

I have "Birds of Africa south of the Sahara, 2nd Ed." by Sinclair & Ryan, but I haven't been able to narrow the ID down past Gull-billed Terns, Whiskered Terns or White-winged Terns. Maybe it's a mixed flock? The variation between individuals, especially those perched, is leading me to confusion.

 

[Jon Turner]

They are 'Marsh' Terns which includes Black, White-winged Black and Whiskered Terns. I can certainly see several White-winged Black Terns, but in amongst the others, I'm not sure...

 

[RafaelMatias]

The first photo includes mostly White-winged Black Terns (also known as White-winged Terns), with 2 clear Whiskered Terns on the extreme right of the image (those with the black hood); there are a few other candidates for Whiskered there, (those that appear to have a longer bill) but cannot confirm those from this image.
On image #2 (in flight) I see only White-winged Black Terns in various moult stages. Key features to confirm are length of bill (should always appear short), any trace of black on the underwing coverts and white-rump; a few that have fully white UWC share the same structure and relative size with the others.
Black Tern is a very rare vagrant to East Africa (I'm not sure there are actually any records on Lake Victoria).

 

[Cabintom]

The first photo includes mostly White-winged Black Terns (also known as White-winged Terns), with 2 clear Whiskered Terns on the extreme right of the image (those with the black hood); there are a few other candidates for Whiskered there, (those that appear to have a longer bill) but cannot confirm those from this image.
On image #2 (in flight) I see only White-winged Black Terns in various moult stages. Key features to confirm are length of bill (should always appear short), any trace of black on the underwing coverts and white-rump; a few that have fully white UWC share the same structure and relative size with the others.
Black Tern is a very rare vagrant to East Africa (I'm not sure there are actually any records on Lake Victoria).

Amazing! Thank you for the detailed explanation.

I know I'm overlooking something, but why was the Gull-billed Tern dismissed as a possibility?

 

[RafaelMatias]

Amazing! Thank you for the detailed explanation.

I know I'm overlooking something, but why was the Gull-billed Tern dismissed as a possibility?

Gull-billed Terns are much larger than any marsh tern, but especially than White-winged Black Terns (it's total length could be almost twice that of WWBT; GBT: 35-42 cm, WWBT: 20-24 cm). Legs are much longer than any other tern and bill quite thick. A Gull-billed Tern among the WWBT would stand out as a sore thumb

 

[foresttwitcher]

There's also a Pied Kingfisher in the first photo.

 

[Cabintom]

There's also a Pied Kingfisher in the first photo.

I have a shot taken down the beach with nearly 30 Pied Kingfishers in it. They're very fun birds to watch.

 

[RafaelMatias]

And by the way, Welcome to Birdforum Cabintom! :t: