Carnon Downs sewerage works and the surrounding area offered up a fairly spectacular, albeit rather bewildering array of various chiffchaff types this morning. I made the final score as follows:
two tristis (one quite vocal),
at least four sub-tristis intergrades displaying the full spectrum of characteristics from almost complete tristis to almost complete abietinus,
3 pure abientinus and
at least 50 collybitta.
Also 4 Firecrests
I also had what I can only imagine was a male hybrid Willow Warbler x Chiffchaff in full song uttering the descending song typical of Willow Warbler interspersed with chiff-chaff chiff-chaff, rather similar to two presumed hybrids I’ve come across previously. Appearance wise, it looked more like a bog-standard chiffchaff with black legs, plumage tones within the range of collybitta (albeit slightly more greeny/yellow than is typical), but with rather long primary projection.
Anybody keen to get their head-around the various plumages and vocals of Chiffchaff races would do well to visit the site over the next few days, particularly as the mild weather seems to be encouraging the birds to be quite vocal.