Arctic vs Eastern Crown
There are many birds out there which are very similar in their features and some are only separated by a tiny bit of difference between them. One of them which intrigues me to find out more are the Arctic and Eastern Crown Wablers. An Eastern Crown is quite similar as an Arctic Warbler (Robson, 2007) but there are several features which can be identified to separate them from each other. Through numerous field trips, comparing notes, photos and listening to the experts, i have managed to distinguish them based on these features:
This is an Eastern Crown Warbler. Like Arctic Warblers, Eastern Crowns are winter visitors/migrants originating from as far as Siberia. Robson (2007) has listed several differences between them but there are a few "fast" and "easy" ways to determine their presence. (1) An Eastern Crown has pale crown stripe and (2) a yellow vent ! In this picture you could see a faint white stripe on top of its head while its vent is yellowish.
This is an Arctic Warbler i believe. It has no crown stripe and certaintly looks much duller (3) than an Eastern Crown. So those are the three quick references one could use to determine whether you are looking at an Eastern Crown or an Arctic warbler in the field. The rest of their differences including their calls can be found in Robson (2007). Hope the above explaination would be of help to new birders and if you have a better and faster way to id these birds please do drop your views here.
According to the experts like Dave and Seng, this bird looks more like an Arctic Warbler and not a Dusky Warbler. This picture was taken more recently in Serendah - Nov 2011.