Tuesday, April 23, 2019

Willy Chiff And Others

After our not very productive ringing of Saturday, and on a slightly marginal forecast, we decided to have another go at Oakenclough on Monday. Well, after all, it is spring when many millions of birds migrate from Africa to Europe, so we might just catch a few. 

I met Andy at 0615 where he was already busy with setting the mist nets in a less than ideal 10 mph breeze but partly sheltered situation. We caught better but with a truncated finish at 1030 due to the ever strengthening easterly wind. 

There was little obvious migration however most of our catch of 15 birds proved to probable migrants - 5 Siskin , 3 Willow Warbler, 2 Blackcap, 2 Lesser Redpoll, 1 Goldfinch, 1 Chiffchaff and 1 Wren. 

This has been a pretty poor year for Lesser Redpolls, our catches below expectations. The two on Monday could well be the last until their autumn migration begins.

Siskin - adult female 

Siskin - tail of adult female 

Siskin - adult male

Lesser Redpoll


Willow Warbler and Chiffchaff are both “phylloscopus” warblers, which means they are in the same bird family as each other. They also look very alike. They are both small birds with slender legs and bill. They both show greyish green and white plumage with no striking features. Field identification isn't helped by the fact that they are both very lively birds; constantly on the move, flicking through the foliage in search of flies and insects. 

Leg colour may be the easiest way to separate Chiffchaff from Willow Warbler, and while it is not fool proof it is mostly a good guideline. Chiffchaffs have black legs and Willow Warblers have light brown, flesh coloured legs. The problem with this feature is that Willow Warbler leg colour can sometimes vary and birds with dark legs have been seen but this is the rare exception to the rule. 

Willow Warblers tend to have  more pronounced supercilium but not always so, especially in the autumn time.  


Willow Warbler

The songs of these birds could not be more different and are well worth learning. Chiffchaff is a very easy song to remember as the bird simply says its name over and over again. A loud chiff-chaff, chiff-chaff, chiff-chaff. The call is a loud "hweet". Willow Warblers have a very fluid like song consisting of descending notes and once learned is easy to remember. Call is a loud "hoo-eet". 

Although both warblers are ground nesters, Chiffchaffs tend to inhabit taller stands of deciduous trees and woodland. Willow Warblers can be found in a variety of habitat, from parks and gardens to hedges and willow copses. While on passage in spring and autumn both warblers can be found virtually anywhere. 

If you ask any experienced birder how to tell Willow Warbler from Chiffchaff, they will tell you that primary projection is the proper way to do it and as so it's worth explaining. It's not as hard as it sounds but it does requires a basic knowledge of bird topography, in particular the different groups of wing feathers and where they are situated. Basically it is the length that the primaries extend past the tertials and how this relates to the tertial length e.g. in the figure below the primary feather projection is only half the length of the tertials in Chiffchaffs. Whereas in Willow Warblers the primary projection is equal to the length of the tertials. 

Wings of Willow Warbler and Chiffchaff - PJ Grant

This “wing formula” gives a Willow Warbler a longer wing and also indicates that Willow Warblers travel further on migration - all the way to tropical Africa compared to Chiffchaff which winters in the Mediterranean and North Africa.

Linking this post to Anni's Birding and to Eileen's Saturday Birds. Take a look.


David M. Gascoigne, said...

Dear Mr. Slade: Based on the last post and on this one it appears that you have developed an obsession with Willies, now even giving them cute little names. Willy Chiff indeed, Hmm, I perhaps need to speak to Sue. Psychiatric intervention may be needed. Thank you also for your arcane coverage of plumage in two similar species. What is grist for the mill for birders and especially banders is probably esoteric and remote to many who will no doubt be fascinated and benefit from such discussions. We plan to set our nets and begin banding this weekend. Hard to believe another spring is already here.

Margaret Birding For Pleasure said...

very well explained Phil between these 2 similar birds

italiafinlandia said...

Love the Blackcap! It sings so melodiously...
Have a nice day!

Rhodesia said...

Love that shot of the Siskins tail it shows the markings so well. The weather is improving here but we have had a couple of wet days that the garden really needed! Hope you are well. Diane

Lowcarb team member said...

I am such a novice about birds, and I learn so much when visiting your blog. Appreciate the information here, thank you.

Have a lovely Friday and hope the weekend is not too windy or stormy!

All the best Jan

Anu said...

Hello Phil. Interesting post. It is often difficult to identify Chiffchaff and Willow warbler. Good think is that they both have their own song.

eileeninmd said...

Hello Phil, great post. Your photos are awesome. I love the Siskins and Redpoll. The Chiffchaff, Blackcap and Will Warbler are sweet birds. Thanks for sharing your post with my critter party. Happy Saturday, enjoy your weekend.

sandyland said...

am i understanding the lesser count is due to migration redpolls?/

Adam Jones said...

Great explanation Phil. I always struggle when they are not in song, which will be most of the summer going forward. I think I'm ok on colouration most of the time, but can never be 100%.

~Lavender Dreamer~ said...

I love learning the songs...especially now when all the leaves are on the trees and we can't always spot the birds. And it's nice to know some of the things to look for when ID ing! There's so much to learn! Thanks for sharing your knowledge!

Anni said...

Learning the different songs/bird calls, I have found is 99% a sure-fire way of IDing birds. But here, there is a catch...in the trees unseen green jays can mock other bird calls a lot. One flew out, where at first I thought I heard a mockingbird. Ironic. This year so far not too many migrants at my hotspots. Enough, but not like its been over the years. Guess the damage from the hurricane diminished their food supply.

Once again, thanks for stopping by I'd Rather B Birdin' and linking in with us birders. I appreciate your loyalty and sharing.

Sallie (FullTime-Life) said...

I’d like to see either one of those birds in real life! (And if I posted a semi-decent picture when I did, I imagine I would ID them wrong and some professional and kind blog/birding friends would correct me. ) At least, that’s what happens with about half of the birds I do see. Thanks for being one of those people!

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