White-tailed Tropicbird Here!!

White-tailed Tropicbird photo Grete Pasch

What a week, the newest addition to our merry band of birders, Grete Pach, is having.  Already this week she has alerted us of the return of the Bat Falcon (Falco rufigularis) in St. James, a bird she first saw and reported on, last year March 20^th.  This is the second record for the island.  She doubled down on her rare bird findings when she and Dr. Webster visited Green Point, St. Philip to see the seasonal Red-billed Tropicbird (Phaethon aethereus) migration.  These birds spend most of the year at sea but are close to the island around this time of the year.  She photographed one of the Tropicbirds with a different winged pattern and shared it with us on our local birding alert platform.  Ed Massiah, our local expert, confirmed her hunch that this was indeed a White-tailed Tropicbird (Phaethon lepturus) and he also added that her sighting was the first ever confirmed land sighting and could be the first recorded breeding attempt for the island.

Separating P. aethereus and P. lepturus

Red-billed Tropicbirds

White-tailed Tropicbird photo Grete Pasch

There may be difficulty in separating these two tropicbird species; both are predominantly white in colour with black markings on the back and wings, also both adults also show the characteristic of a long white tail feather which is synonymous with these sea birds, but there are a few differences that will help with the correct identification.  First, note the wing patterns when seen in flight, that is the way we normally see them; in the Red-tailed Tropicbird the black markings are on the outer feathers or primary feathers while in the White-tailed Tropicbird along with the black primary markings they also have additional black markings on the inner wings or carpal bar which appears in a V shape looking down on the bird in flight. Size isanother identifying mark.  The White-tailed Tropicbird is marginally smaller than the Red-billed though this may not be always obvious in the field.  Finally the bill colour is also a factor with the Red-billed having a bright red bill while the White-tailed has a yellowish one.  The bill colour can be used as an identification marker in St. Philip, because the birds seen there are normally adult birds but it should be noted that the bills of the juvenile Red-bills are also yellow.

I will try to see both birds in the coming days.  If seen, the White-tailed Tropicbird would be a lifer and the Bat Falcon a yearer for me.  I will let you know how my birding goes, until then enjoy your birding.

References

• Tropicbird Identification by Don Roberson