Pink-footed Geese flock over the marshes at Lady Anne's Drive
Ever
since the days of the Victorian ‘gentleman gunners’, the wildfowlers and
collectors of the distant past, Holkham has maintained its place as being one
of the most consistent spots in the UK for attracting large numbers of wild geese. It was only
during and after the Second World War with disturbance from heavy artillery
fire that the vast skeins of Pink-footed Geese, the species that Holkham became
synonymous with, temporarily deserted us. Holkham fits nicely into the
ornithological history books not only for having one of the largest
concentrations of ‘Pinkfeet’ in Norfolk when some 90,000 were estimated to be
present on a single day back in 2006 but also for providing the county with its
very first example. Pink-footed Geese, with their pink legs and feet are very
similar to Bean Geese (with their orange legs and feet) and in Victorian times
they were deemed one and the same. It took until 1833 before it was realised
that two species were actually involved and how fitting it was that the first
Norfolk Pinkfoot should be shot at Holkham. Incidentally that very first one
was preserved and is still on display within Holkham Hall. This year Pinkfeet
numbers have only managed to reach 33,000 on the reserve, still a significant
total but far less than the 2006 count! Reasons for such a drop include less
sugar beet being grown locally (the harvested yet unwanted tops and leaves left
in fields are the main winter food source) and milder weather and more food in
Scotland.
A flock of Dark-bellied Brent Geese rise up from Burnham Overy marsh.
Apart
from the Pinkfeet there are other species of wild geese that arrive each winter
to seek food and sanctuary on the protected marshes of the north Norfolk coast,
Holkham in particular. Probably most well-known to casual observers, second
after the Pinkfeet would be the Brent Geese. Brents are smaller and darker and
part of a different family of geese. Our geese come into two distinct groups; Anser or ‘grey geese’ like the Pinkfeet
and common feral Greylags or Branta otherwise
known as ‘black geese’ such as
Canada, Barnacle and Brent Geese. Like many species of geese there are distinct
sub geographical groups; different populations from distinct parts of the
World. They might all nest in a certain area and then winter in another
distinct area well away from others of their kind. Birds such as Barnacle Geese
cover several widely separated areas of the Arctic in which they nest yet
usually stay well apart in the winter but essentially they all look identical.
The difference in the various Brent geese is that they have evolved so that
they actually look different in different parts of their range. Here at Holkham
we have been lucky as we have been able to see and compare these different
forms. At the moment they are all deemed as identifiable sub-species yet with
evolution still ongoing and the taxonomic scientists working overtime they
might at some point all become species in their own right.
The common form of Brent Goose seen in Norfolk is the 'Dark-bellied'
The
common form we see here in north Norfolk is the Dark-bellied Brent Goose. It
arrives every September from breeding grounds on the tundra from northern and
central Siberia and peaks at about 5000 feeding on short coastal grassland, cereal,
saltmarshes and mudflats although numbers are far less than they were 20 years
ago. Less common is the Pale-bellied Brent Goose. It nests in the Greenland,
Canadian High Arctic, and Svalbard. Small numbers from the latter two
populations appear in Norfolk amidst the Dark-bellied birds, with the Greenland
birds most likely to be seen amongst the wintering Pinkfeet. A far rarer form,
the Black Brant can be seen in even smaller numbers here in Norfolk, usually a
couple per year. This form breeds from the central high Arctic Canada across to
the Pacific coast of both North America and Asia. This is where things really
start to become confusing (or interesting!) as where Dark-bellieds and Brants
meet there is occasionally inter-breeding.
The less numerous Pale-bellied Brent Goose
The striking looking black and white goose in the centre is the rare Black Brant
All
geese traditionally remain a tight family unit during their first year, even
during their migration south, it means when we see goose flocks here in the
winter we can see both parentage and the amount of youngsters in each family. This
year has seen an almost complete failing of the breeding Brent Geese, hardly
any young in evidence and a phenomenon that frequently occurs. The success and
failings of Arctic breeding Brent Geese is linked to the availability and
abundance of rodents for predators such as Arctic Foxes. No Lemmings means baby
geese are sought after as prey. What we have seen here at Holkham currently amidst
the flocks of Brent Geese are all the different forms together in the same
flock including some of those hybrids. Such identification conundrums have
stirred up much interest from visiting birdwatchers at Lady Anne’s Drive, where
the flock habitually frequents.
The birdwatcher's conundrum - one of our regularly occurring hybrid birds
Even
more unusual for us this year is a potential English first – a Grey-bellied Brant.
This fourth form in the Brent goose group of sub species has only recently been
truly recognised (although some scientists are still arguing this!). It breeds
in a relatively small area of western High Arctic Canada and winters solely in Puget
Sound, western USA. In looks it appears intermediate between Black Brant and
Pale-bellied and some observers initially thought they were hybrids although
ongoing work has suggested that is not the case. The odd bird has turned up in Ireland but never in England so when a bird turned up amongst
the Pinkfeet this October at Wells and then at Burnham Overy in November it
proved a very exciting find for avid local goose-watchers. With scientific work
continuing and evolution obviously very much ongoing it could be we have to
wait quite some time before the mysteries of the whole Brent Goose group truly
unravels. In the meantime have a look and you will see that everything is not
quite just black and white!
This year's Grey-bellied Brant - a potential English first ?
Andy
Bloomfield
Warden