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Record Numbers of Little
Egrets in the North West
By Steve Williams (published in
Vol 1 No 8 August 2004 of the BNW magazine).
Little Egrets have been
increasing in Britain for the last twenty five years following a
northwards expansion of its breeding range within France, with a
dramatic increase in the last ten years with breeding occurring annually
now in Britain. Prior to 1989 it was a rare vagrant to Britain, but
during that summer about 50 birds occurred in the country and subsequent
summers the numbers increased with, for example, about 200 in 1993, 650
in 1995 and over 1,000 were counted nationwide by WeBS (the Wetland Bird
Survey) in 1999.
A similar increase has been recorded in the North West during this time;
albeit much smaller and more recently than southern Britain, as would be
expected for a northerly expansion. The first successful breeding in our
region (and indeed northern Britain) occurred at Frodsham, Cheshire,
during the summer of 2001; breeding has been confirmed elsewhere in the
region since.
Each summer from July onwards, Little Egrets have a post-breeding
dispersal and there is a strong north-westerly movement from their main
breeding strongholds in southern Europe, particularly France. It is
thought that these birds have overwintered and remained to breed in new
areas. These birds continue to supplement the increasing British
breeding population and September and October are the peak months for
Little Egrets in Britain, with numbers then declining as birds move back
towards their breeding grounds or indeed migrate further south; birds
from southern French and Spanish breeding colonies typically migrate
southwest into Africa.
There are now good numbers remaining to overwinter in Britain and in the
North West. However, the mortality rate for overwintering birds in
northern Europe is apparently quite high, due mainly to poor weather.
The two main roost
sites in the North West during the summer and early autumn months are at
Inner Marsh Farm RSPB Reserve in Cheshire ('IMF') and Aber Ogwen in
Conwy. During July and August 2004 numbers built up gradually at these
two sites to respective record numbers of 68 at Aber Ogwen on 17th and
52 at IMF on 3151 August. The maximum combined count was 108 also on
17th August when there were 40 counted at IMF.
The histogram below indicates the numbers of Little Egrets recorded at
IMF and Aber Ogwen during July and August 2004 (the data is not
complete; i.e. a null count does not necessarily mean that there were no
birds, just that there was no count done that day).
It is interesting to
note that there appears to be a similar build up at both sites, although
the build up at IMF appears to be slightly later than Aber Ogwen,
perhaps to be expected for a more northerly site.
The data does not assist with determining whether birds move between
these two sites, other than those counts on 10th, 17th and 18th when
counts were made at both sites and anecdotal evidence suggests there is
little or no movement between the two. However, only by colour-ringing
birds would this be proven one way or the other.
The roost at Aber Ogwen is a tidal roost. A few birds are seen on the
pool in front of the hide on 'The Spinnies' reserve (North Wales
Wildlife Trust Reserve), however, the vast majority can be counted on
the opposite shoreline as the tide rises.
This contrasts with the roost at IMF which is an overnight roost site,
for birds feeding mainly on the Dee Estuary during the day. A few birds
start to gather on the No 1 lagoon early evening (see photograph above)
and these are then supplemented by further birds arriving in small
groups until just before dusk.
|
Gary Bellingham ©
Little Egret at Burton.
|
I watched 40 birds,
which had gathered on the No 1 lagoon at IMF, fly up and around the
reserve in one single flock on 17th August. They flew around for a
couple of minutes before alighting in a tree in Marsh Covert,
presumably to roost for the night. A fantastic sight!
As stated above
there is no evidence of movement between these two sites, with only
the odd single recorded at sites between these two roosts.
Presumably if birds were travelling to IMF to roost overnight from
sites other than the Dee they would be recorded 'en route'. All of
the birds arriving at IMF tend to arrive from between Burton Point
and the Barn Field, indicating an arrival from the Dee.
Little Egrets were
recorded at several other sites between the Glasyn Estuary, Gwynedd,
in the south and the Solway Estuary, Cumbria, in the north of our
region during August, with between 1 and 5 birds recorded at each
site. There were at least 130 Little Egrets in the North West during
August, although the figure is more likely to be in excess of ISO. |
There may well be a further increase in Little Egrets in the region
during September and we can possibly look forward to an increase in the
wintering population compared to previous years and a subsequent
increase in breeding activity in the North West next year and beyond.
Steve Williams - September 2004
References:
Cheshire and Wirral Ornithological Society ('CAWOS') 2001, Cheshire and
Wirral Bird Report (CA WaS) British Trust for Ornithology, 2002 - The
Migration Atlas (T & AD Poyser)
Cramp S (Editor) 1977 - Birds of the Western Palaearctic Volume 1 (RSPB)
Acknowledgements:
Inner Marsh Farm RSPB Reserve (Colin E Wells - RSPB Site Manager Dee
Estuary)
Numbers from Aber Ogwen and elsewhere (Ted Abraham at Birdline North
West)
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