Monday, 27 August 2012

Willows passing through..

It's been noticeable over the past few weeks,  the soft 'wheet'  contact calls of our most abundant summer migrant: the Willow Warbler.  After the breeding season I usually notice a rush of migrants around the garden, from late July into August.  They are restless and move from Willow scrub down to perennial plants and even forage on the lawn: small insect prey is found in all these places at this time of the year. 

Many of the first year birds are beginning the first tentative movements south, culminating in an arrival in West Africa, via Iberia, in late autumn / early winter, all going well.

Willow Warbler  (c. John Fox)

Willow warblers are showing a trend of increase on the Countryside Bird Survey, occurring in 70% of 1km squares surveyed.  However once the pleasant summer song abates in early summer, they are a little more difficult to locate, and indeed separate from their close relation, the Chiffchaff.  

Chiffchaff  (c. David Dillon)
In seeking to separate the two close relatives (both are no bigger than a Blue Tit in size), note the colour of legs and feet: black in Chiffchaff, a bright yellowish in Willow Warblers. Chiffchaffs are generally duller in colour tone, and more 'plain faced'.  The wing length is noticeably longer in Willow Warbler, compared to Chiffchaff.  Both are restless and flick wings and tail as they move through cover, sometimes hovering around large, cracked, autumn leaves of the Sycamore tree: occasionally you can even hear them snap their beaks on insect prey, fuelling up for the long journey south!

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