Pale bellied Brent (part 1)

For my Saturday's post I am going to tell you the story of the

 

 Pale bellied Brent goose (Part 1)

 

and I may take several posts to complete it.  In Northern Ireland we have Pale bellied Brent and that is mainly the ones I will be showing you. 

One of the main areas that they arrive at is Strangford Lough which is a large sea loch or inlet in Country Down, Northern Ireland. It is separated from the Irish Sea by the Ards Penninsula. The name Strangford is derived from Old Norse: Strangr-fjorðr meaning "strong fjord"; describing the fast-flowing narrows at its mouth. It is called Loch Cuan in Irish, meaning "calm lough" (describing the still shallow waters of the mud flats)

 

 

Pale bellied Brent Geese

 

 

 

 

There are 3 forms of Brent Geese.

1. Dark-bellied  - nominate
2. Light-bellied – hrota
3. Black Brant – nigricans

 

 

1. Pale bellied Brent - form B.b.hrota, which breeds in Spitsbergen, Canada and Greenland has pale grey-brown underparts.

The Brent Goose is smaller and much darker overall than the other 'black geese' and has a shorter, thicker neck, marked in the adults by a little white smudgy half collar. From a distance they can look all dark apart from the gleaming white under-tail area. The pale-bellied form looks much cleaner and more attractive.

Length:  60cm

Voice: Flocks of Brent Geese produce deep rumbling, almost purring, sounds audible at great distances.

Sexes similar.

Ageing: Juvenile similar to adult, but head, neck and breast a duller brownish-black. Juveniles lack the white neck patch of the adults. Full adult plumage attained during first summer.

 

 

2. The Dark-bellied Siberian form B.b.bernicla has slate grey underparts.  Dark-bellied Brents occur widely on the East and South coasts of Britain, best seen at sites such as Cley on the north Norfolk Coast.

 

 

 

3.  Brant - The American and eastern Siberian race B.b.nigricans is blacker with contrasting white flanks and very raely seen in the UK.

 

 

Food

Previously fed exclusively on estuarine plants such as Eel Grass and seaweeds but has now adapted to feed on crops such as barley, wheat and oilseed rape. Occasionally takes molluscs and similar foodstuffs.

All 3 forms love eel grass -

They are all -: 

Marine living
Very long distance migrants
5000Km round trip
Population increase from 20  - 40 thousand
Terrestrial feeding

 

 

In April, brent geese leave the UK and Ireland and head north again. The pale-bellied brent geese stop over in Iceland. Here they fatten up, increasing their weight by up to 40 % in preparation for the final 3,000 km (1,865 mile) flight over frozen Greenland to their breeding grounds in Canada. 

 

 

Above and below Brent feeding in Iceland

 

That is their 1^st staging ground and there are 24 sites.  This is a crucial staging site and researchers are not only tagging, and counting the birds they are looking at their bellies to see how big they are.  By this they know how much fat resources they have for moving on and the possibilities of having a good breeding year.  In Iceland they will find lots of Zostera beds to feed and fatten up on.  Female birds always put on more weight than males as they need it more for breeding and migragation.  They also take blood samples from all birds and this enables them to know what food they are been eating over the last month and what sites they were feeding at.

 

 

 

 

Then by May/June they fly to Greenland and they reach Eastern Queen Elizabeth Islands, Canada by July where they start breeding. 

 

Eggs: 3-5
Incubation: 24-26 days
Maximum lifespan: 19 years
Length: 56-61cm
Wingspan: 110-120cm
Weight: 1,300-1,600g
Ireland wintering: 34,000 birds

 

The Brent geese pair for life. In the Canadian Arctic they nest within 10km of the coast. They mainly nest colonially close to water in small groups on coastal islets or small islands within inland lakes

 

They make a small scrape in the gravel, on the south side of rocks were the snow is melting.  They lay their eggs and when they are hatched the chicks only weigh 100g.  However 2 weeks later they weigh 1 Km.   That is a hugh growth but it is a very short breeding season.  The main predators are the Artic foxes and some Polar bears.  By the time the Brent are ready to leave for their wintering ground, they weigh 1.4 Kilos.

 

The Brent Geese feed mostly on vegetation but molluscs, crustaceans and lugworms are taken. A wide variety of plants are grazed or torn or pulled up underwater or when drifting. Plants covered by the tide are taken by up ending or swimming with the head and neck below the water. At low tide rhizomes are exposed or loosened from mud by grubbing and trampling. In the breeding grounds of the arctic food includes algae, mosses, lichens and the stalks of grasses and herbs. Winter feeding is on mudflats where it favours eel grass and cultivated fields of winter cereals and oil seed rape.

 

In August and September they fly back, with their young, to their winter home at Strangford Lough, Northern Ireland, a round trip of 9,000 miles. During the trip the birds face many dangers, including hunters, predators, bad weather and 3,000-metre ice mountains in Greenland. 

  
Now I have a short video that can be accessed at

http://youtu.be/gy1rCSHuJCk

If there is a black space below, click it and the video will appear.

 

Now I think that is enough for today. I hope you enjoyed the Brent Geese and as I am on holiday at present and do not have the time to make part 2 at the moment, so I will keep it until next Saturday's post.

Many thanks for visiting and for your comments.