House (Pacific) Swallow collecting nesting material
Posted by BESG on 7 October 09, Wednesday
Contributed by Dato' Dr Amar-Singh HSS
Dato’ Dr Amar-Singh HSS encountered a pair of Pacific Swallow (Hirundo tahitica javanica) at Tambun Interior, Perak, Malaysia on 18th July 2009. An adult was carrying a piece of nesting material accompanied by its mate.
“Notice that in the composite image on the left, the pair is very different in their colour scheme. The one in the foreground with the straw for the nest has a less rich plumage, especially the mantle.
“The difference is not just due to lighting (they were in the same light, same angle, just could not focus on both together). It is not supposedly possible to separate male from females (in filed guides, literature) but I would say the lighter one is a female.
“One possibility is the lighter one has recently become an adult and has not developed full plumage yet? Another is that the male has developed a richer “breeding” plumage? Any comments would be welcome. Usually only one of the pair collects nesting material (Smythies, 1999).”
Reference:
Smythies, B. E., 1999. Birds of Borneo. Natural History Publications & The Sabah Society, Kota Kinabalu. (4th ed., revised). 853 pp.
All images by Amar-Singh HSS (Dato, Dr)
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Categories: Morphology-Develop., Nesting
Comment by Subaraj
Made Wednesday, 7 of October , 2009 at 7:15 am
I believe that the bird in the foreground is a sub-adult. The key feature that is still visible to indicate that it has not fully become an adult, is its pale gape.
There also appears to be a little white showing on the dorsal of the bird, which usually indicates some moulting is still taking place.
Is this sub-adult mature enough to be paired off and contemplate nesting? Or, is the collecting of nest material merely a practice session? I think that the latter is more likely as many immature birds are known to conduct such practice sessions.
Comment by Amar-Singh
Made Thursday, 8 of October , 2009 at 6:54 pm
The editor of Oriental Bird Images (Krys Kazmierczak) made this
comment about the images when I posted them, there: “It is possible that the left-hand bird is simply more worn and
bleached from the sun.”
