| |
Last month we looked at
the Acrocephalus warblers, sometimes known
as the reed warblers, because they largely
(but by no means exclusively) favour damp
habitats, including marshes and reedbeds.
This month (and for the following two
months) we will look at the Phylloscopus
warblers, which are often known as the
leaf warblers. This is because many in
this group are rather greenish in colour,
like leaves, and because many are found
in wooded areas and forest, where they
typically search for small insects in
the canopy of trees and in the bushy undergrowth.
However, as we shall see, there are several
exceptions to this generalisation and
as a group in North India, the leaf warblers
occupy probably the widest range of habitats
of any warbler group. Indeed, for people
starting birdwatching in our region, their
first encounters with warblers are most
likely to be of this group.
The Phylloscopus warblers are
generally small and rather dainty, with
fine bills (finer and shorter than Acrocephalus),
and rather short tails, which are sometimes
slightly forked. They are extremely active,
flitting through foliage, flicking their
wings and sometimes hovering. It is useful
to note such behaviour. It is during this
rapid movement that one gets glimpses
of plumage features that may be important
for identification. The overall plumage
colour on the upperparts is greenish in
most species, but the tone of the green
varies greatly between species, from grey
olive green to bright mossy green, whereas
some species have a browner hue. The underparts
are paler, usually washed white or yellow,
but again this varies between species.
However, general plumage tone is not always
a reliable basis for identification as
it will vary according to how fresh the
plumage is (i.e. has the bird recently
moulted) or the light conditions. It is
also rather subjective. So far better
to put effort into looking for distinct
plumage features as well. In the case
of Phylloscopus warblers this
means looking for wing bars (or the absence
of), head pattern (eyestripe, supercilium
and any crown stripes), the colour of
the rump and any white on the tail. The
colour of the bill (especially lower mandible)
and legs are useful to record as well.
You would be very lucky to get views of
all these parts of the bird in one go.
Watching leaf warblers is a bit like doing
a jigsaw puzzle: you get a view of a wing,
and then a few seconds later the side
of the head, then briefly the rump as
the bird hovers for a bit and so on. One
has to piece together a series of snapshots,
and always jot them straight down into
a notebook before looking at the bird
book. Finally, many of the leaf warblers
call whilst they forage, so do note down
a description of the call as well, as
this can be very important.
All of the leaf warblers seen in the vicinity
of Delhi are either passage migrants or
winter visitors (there are three regular
wintering species: Common Chiffchaff,
Hume’s Warbler and the scarce Brook’s
Leaf Warbler). However, some of the species
covered in this feature breed nearby in
the Himalayan foothills, so it is certainly
possible to enjoy watching Phylloscopus
warblers throughout the year within easy
reach of Delhi. And I really do mean enjoy,
as the group includes some of the most
delightful and exquisite birds to be found
anywhere!
The species that will be covered this
month are all rather plain, lacking distinct
wingbars or crown stripes.
|
|
