22 October 2015

Getting collared by a goose

Geese are one a special group of birds that can divide people's opinion in the same way that city pigeons or urban gulls can. Many assume that geese stay in the same place year after year, especially the ones that are fed in parks and urban areas. No one really knows for sure however and ringing is uniquely set up to be able to find this out.

Canada Geese taken by John Harding

One particular issue people have is that when geese moult during June or July, they drop all their flight feathers simultaneously and become flightless. Due to the fear of predation they remain very close to bodies of water for the month or so while they regrow their feathers. Geese can cause serious habitat degradation in certain locations like the reed beds at Hickling Board, Norfolk (.pdf) and understanding more about the reasons behind this can improve the situation for geese and people.

On our BTO Nunnery Lakes reserve, Thetford, Norfolk we have several fishing lakes and the geese usually choose the lake that has fencing around it. The downside of this decision is that the geese quickly eat all the accessible food and they have to be moved out onto another lake. During this process the geese are ringed, and in 2012 our ringers started to add uniquely coded plastic neck collars to Greylag and Canada Geese as part of the Hickling Broad project.

Canada Goose AEL - taken by Neil Calbrade

Neck collars are a safe marking method for large geese and have been used widely in previous studies on species such as the migratory Pink-footed Goose and White-fronted Goose, allowing individuals to be identified when on water as well as on land. This is particularly important if you are investigating moulting birds, where seeing their legs are an issue. Due to the size of the goose's head the collars actually have quite a lot of room inside to move around.

Greylag FHA bringing up the next generation - taken by Janet Foster

Since 2012, we have had a fantastic response from BTO staff, volunteers and members of the public who have submitted sightings of any geese with neck collars to www.ring.ac, specifying the species, combination on the colour ring, location (ideally with a grid reference) and the date.

The map below shows the sightings that we received between summer 2012 to summer 2014 away from the reserve itself. As you can see they did indeed go into town but also they explored the surrounding waterways and lakes.

What is amazing however, is after the summer of 2014 the geese were spotted much further away from the BTO reserve, see map below. The reason for this are under investigation and some individuals regularly return to the BTO after making these 'unusual' movements. Being able to identify each individual on the water should help us answer some interesting questions like 'do geese moult in the same place every year', 'do they winter in the same locations' and 'why do they move'.

If you do see a neck collared goose, please report it via www.ring.ac and you will receive information on the movements of that particular goose and at the same time increase our understanding of these birds.

1 comment:

  1. I have Only just seen this. I was involved in a Yorkshire group studying exactly this using leg colour rings in the early 1980s. I’m not sure who would have the data now? Possibly Yorkshire Wildlife Trust. Malcolm Olgivie (formerly of Slimbridge then Islay) was involved.