Evan Beaver wrote:
Birders, some musings while procrastinating...
When a bird comes into breeding plumage what actually must happen. Are
feathers like hair, in that once they're grown the colour can't be
changed?
In which case, for a change to breeding plumage the feathers must be
shed,
and then a new one grown in it's place, or do they grow the new feathers
before the old ones fall out? It should make for some scruffy looking
birds
in their change in that case. I'm mostly wondering because there's a
Crested
Pigeon that comes to visit every morning, and it's colour seems to be
slowly
changing, becoming more vivid and contrasting, and I'm wondering if I'm
imagining it.
Any ideas?
Hi Evan,
Feathers grow from the base outwards, but many colour changes are are
caused by the outermost part of the feathers wearing away, revealing
colour underneath. This isi certainly the case with male House
Sparrrows, where the dark bib is in winter masked by the pale outer ends
of the breast feathers, but becomes visible in spring.
No change of the feathers themselves.
But I believe some species manage two moults per annum, so this wearing
off may not cause colour change in all species.
Anthea Fleming
freezing in Melbourne
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