Archive for January, 2008

Ray Collier Country Diary – Osprey

Sunday, January 20th, 2008

Osprey – 14th January 2008

There are various ways in which birds in the Highlands are studied and surveyed, sometimes by professionals although the majority are by people who undertake this important work in their own time. Wintering flocks of geese, ducks and waders around the coasts and firths are of international importance and the areas are counted on set days so that the figures can be compared with previous years. Breeding surveys vary from national counts of herons to aerial photographs of gannetries. The various re-introduction programmes of birds such as sea eagles and red kites have to be backed up by intense monitoring often with miniature radios involved. Although there is a great deal of expense in releasing such birds the follow up work is equally important. One of the success stories of the Highlands is the comeback of the ospreys and much of what we know about them is from radio tracking.
There is one scheme that forms the basis of, amongst other aspects, knowledge of the movements of birds whether they are on migration or shorter movements because of weather. The essential requirement of such studies is to be able to recognise individual birds and one important way of doing this is to ring birds. In the Highlands these studies are undertaken by the Highland Ringing Group and the ringing varies from birds in gardens to long term studies on islands such as Canna in the Western Isles. The Group has about 30 dedicated amateur ornithologists and the main aim of ringing the birds is to further our knowledge of survival rates, dispersal rates and migration. Many readers will have come across a ringed bird at one time or another such as a bird in the garden. This is not surprising as the Group rings around 35,000 birds each year comprising of over 100 species. These vary from over 2,000 siskins to 8 golden eagles.
Ringers have to undertake a thorough programme of training and initially for some time under the instructions of a qualified ringer. The welfare of the bird is paramount at all times and studies have shown that the ring or rings cause absolutely no inconvenience to any bird at all. At one time ringing was virtually confined to the world of the ringers themselves, and the birds, but these days ringers get involved with local communities throughout the Highlands and increasingly schools are given demonstrations and the thrill youngsters get on seeing birds close too makes it all worthwhile.
Ringing can give an insight into a bird’s life and such was the case of an oystercatcher that hatched in 1976 and was ringed in Inverness at the Longman in 1978. It was caught again at Alterlie Point just east of Inverness in 1991 and as the ring was worn it was re-ringed. It was found freshly dead near Farr, just south of Inverness in 2004 so the age at death was a staggering 28 years. Many birds do not live this long and many small birds may only survive for a couple of years. The ringing scheme only works if the birds are found or seen again and readers can help by examining any dead or injured bird they find. The number of the ring should be carefully noted plus the location with a grid reference if possible. If the bird is dead then the ring itself can be sent off. Other details can include the species of bird and the cause of death. Do not forget to put in your own name and address and whether you want the ring to be returned to you. Information should be sent to British Trust for Ornithology, The Nunnery, Thetford, Norfolk. IP24 2PU.

Ray Collier Country Diary – Otter tracks

Sunday, January 20th, 2008

Otter tracks- 7th January 2008

In summer, Loch Farr, that lies a few miles south of Inverness, is vibrant with wildlife such as fish, birds, mammals and amphibians. The richness is partly because of the very large numbers of smallish brown trout and partly because of the aquatic plant life. The loch is comparatively shallow so the aquatic plants grow almost all over the loch and these support very large numbers of insects. The insects attract large numbers of birds and the fish that seem constantly rising to them. On a calm day, with the trout rising and toads and palmate newts coming up for air, the water seems teeming with life. In contrast at this time of the year the loch appears lifeless as if stopped in time and yet the wildlife itself must still be there.
The changes for wildlife to winter starts in the late autumn when the yellow fringe to the loch is larch trees needles that have changed colour before being shed. The changes are brought about mainly by the length of daylight hours and temperature and whilst some wildlife leaves the water others stay and survive as best they can. The brown trout lies near the bottom for the winter and it just slows down some of its body functions so that it does not need to eat although just occasionally it may feed on whatever it can find. This makes the fish sluggish and no doubt makes it easier for otters, that have no choice about winter feeding, to catch them. The otters are secretive but tracks in the sand give them away. By the end of the winter the brown trout are very thin and so much so that many anglers do not fish until well into the season to give the fish a chance to feed up.
The very large numbers of toads in Loch Farr simply leave the water and hibernate on land in a variety of places. Normally they all move to roughly the same area but at Loch Farr the toads are so widespread they appear to spend the winter virtually all around the loch. Holes in the ground, cracks in peat and under stones are used and in some places such as sand or loose soil they may even bury themselves. The reason toads leave the water is that they have to come to the surface to breathe and if the water was to ice over they may well suffocate. Unfortunately, at the west end of Loch Farr there is a short stretch of road and some of the toads move across it to their hibernating place. The movement in the autumn is staggered so few toads get run over but in the spring if the conditions are right such as a sudden warm night with rain hundreds of toads may be on the move. One year well over 200 toads were run over in the space of two nights.
In contrast frogs can breathe in oxygen through their skin and extract it from water so they do not have the need to keep going to the surface. Therefore many choose to stay in the water to hibernate although they move to land via feeder burns if the water freezes too much. The palmate newts also leave the loch and hibernate under stones or in crevices and sometimes many hibernate together in a communal place. So the wildlife is still there, whether in the water or on land, although unseen to our eyes. It is all waiting for the longer days and increasing temperatures and then the life cycle will start all over again and the loch will be vibrant once more.