[Jacamar]

I saw some swallows yesterday that I think might be Bank Swallows (Riparia riparia), but I am not good at identifying swallows. They were white underneath with a grey band across the breast; making a sort of white collar. An inch-long thin grey line extended from the breast band down the middle of the front. I could not tell what color the back was. Around sunset they were flying out of the sugarcane fields and perching on the electric wires along the road. I estimated that there were 1-2 thousand of them covering the wires. Does anyone know if these would could Bank Swallows?
Thanks!

[Rasmus Boegh]

Could very well be Bank Swallow. But, carefull: Brown-chested Martin (especially migrant ssp. fusca)...

[Jacamar]

What are the main differences? The Brown-chested Martin doesn't seem to have a white collar; the bird I saw did. Isn't the thin brown line extending from the breastband a good identifying feature?

[crispycreme]

Originally Posted by Jacamar

Isn't the thin brown line extending from the breastband a good identifying feature?

I would say not necessarily, since the BC Martin can have a similar thin line down the breast:

http://www.arthurgrosset.com/sabirds...%20martin.html

Look in particular at pics #2 and #4.

However, it seems far more prevalent and noticable on the Bank Swallow than on the martin, so I would say your first instinct is probably correct.

[Rasmus Boegh]

Originally Posted by Jacamar

What are the main differences? The Brown-chested Martin doesn't seem to have a white collar; the bird I saw did. Isn't the thin brown line extending from the breastband a good identifying feature?

The migrant sub-species fusca of Brown-chested Martin often has a rather similar whitish half-collar and, more importantly, a brown "line" extending down from the chest-band. This "line" is usually wider than in Bank Swallow, but soon it becomes more of a bunch of closely placed spots. From afar it isn't possible to see that they are spots. Main feature is size (i.e. a Martin compared to a Swallow) and the fact that Bank Swallow generally is paler brown than Brown-chested. This is why I mentioned that you should be careful with the ssp. fusca of Brown-chested Martin...

[Rasmus Boegh]

Finally, it should be mentioned that normally most Bank Swallow should be out of Guyana by now. They usually leave before may, so it would be somewhat late...(though not impossible)

[Jacamar]

Thats interesting... because I see these birds from about May - September or so and then they disappear for the winter months; reappearing again the next May. Would that mean that they couldn't be Bank Swallows?

[Rasmus Boegh]

Originally Posted by Jacamar

Thats interesting... because I see these birds from about May - September or so and then they disappear for the winter months; reappearing again the next May. Would that mean that they couldn't be Bank Swallows?

If you usually see them from May to Septemeber, they are probably Brown-chested Martins ssp. fusca... Why? Well, this ssp. of Brown-chested Martin breeds further south in South America, then go north for the winter (which, in the Southern Hemiphere, is roughly from May to September). So, the time you see the swallows, is exactly the time you would expect to see Brown-chested Martins of the subspecies fusca!!!

Then, what about the Bank Swallow. They spend the summer further north, USA and alike where they breed. In the (North Hemisphere) winter most fly to South America. So, you should expect to see those from ~September to April! ...and, many of the Bank Swallows spend the winter further south than Guyana, hence many are only present as passers through. Either on the way to their wintering quarters in Brazil/Argentina or on the way back to North America...

[Rasmus Boegh]

Originally Posted by crispycreme

I would say not necessarily, since the BC Martin can have a similar thin line down the breast:

http://www.arthurgrosset.com/sabirds...%20martin.html

Look in particular at pics #2 and #4.

However, it seems far more prevalent and noticable on the Bank Swallow than on the martin, so I would say your first instinct is probably correct.

Careful! Arthur Grosset made a small mistake. It's the bird on photo four that is ssp. fusca, not (as he writes) photo two. I have just send an email to him, and it will presumeably be corrected soon.

[Jacamar]

So what details do you suggest I look for next time I see them?

[Rasmus Boegh]

Originally Posted by Rasmus Boegh

Main feature is size (i.e. a Martin compared to a Swallow) and the fact that Bank Swallow generally is paler brown than Brown-chested.

What is mentioned in above quote...

[Rasmus Boegh]

Perhaps it should also be mentioned that Bank Swallow usually has a rather distinctive fast and "flittering" flight... compared to the more languid flight style of Brown-chested Martin

[Jacamar]

These birds are comparabale in size to the Gray-breasted Martin. In flight they alternate between beating their wings and soaring; they're not fast either.

[Jacamar]

They are also bigger than the White-winged Swallow; which (I think) are average sized swallows.

[Rasmus Boegh]

Everything indicates that what you have been seeing are ssp. fusca of Brown-chested Martin. Time of year you see them, flight behavior and size; everything fits. Actually, Bank Swallow is slightly smaller than White-winged Swallow...

[Jacamar]

Thank you very much Rasmus. I am glad I finally got an ID resolved; a few of the others weren't figured out. So the scientific name is Progne fusca?

[Rasmus Boegh]

Originally Posted by Jacamar

Thank you very much Rasmus. I am glad I finally got an ID resolved; a few of the others weren't figured out. So the scientific name is Progne fusca?

No, fusca is only the name of the sub-species. Full name in latin would be:

Progne tapera fusca

[Jacamar]

Thank you again!