Studies

Golden Eagle

I have been monitoring breeding golden eagles in the Scottish
Highlands for over thirty years. Eagles need open ground to hunt over and undisturbed cliffs or trees to nest in. These are limited resources which are progressively intruded upon by human activities. In recent years much of my work on these birds has been related to possible impacts of windfarms on their use of nest sites and hunting areas. Over the years I have seen several nest sites abandoned by breeding eagles, and this has been probably due to disturbance by various types of human intrusion. In such cases the birds tend to shift to other less public eyries. However, the main damage being done to eagles, and all raptors in Scotland, is deliberate killing, such as in areas managed for grouse moors. This is a serious effect, as it removes breeding birds from the Scottish population. This is a deliberate illegal act, when will it be stopped.
   
 
Rock Ptarmigan
These are alpine/arctic birds and my main interest has been in 
why these birds live on some Scottish mountains but not others. This has involved identifying what foods they prefer and where they seek cover from weather and predators. They are most numerous on hillsides, where there is abundant blaeberry and crowberry, their main foods, interspersed with patches of rock or boulders which they use for cover. As these birds live on the mountain tops they might be vulnerable to global warming. Simple annual counts of  birds are unlikely to provide any definitive information on such an effect on ptarmigan however, for their numbers vary in approximately 10-year cycles and populations on different hill massifs are not synchronised. To fully understand how ptarmigan might be affected by any change in the climate, it would be more suitable to study their numbers and breeding success in current different environmental patterns.  
 
 

Dotterel

I have studied these birds privately for many years and professionally since 1987, 
including seven years with Scottish Natural Heritage. Dotterel are small plovers which breed on the high tops of the Highlands, on short wind-swept heath. They have a sex role reversal where the females are the larger, more brightly marked sex. Once they lay the eggs the females leave the males to incubate them and rear the chicks alone. These birds spend winter in north Africa and only come to Scotland to breed. Their numbers fluctuate between years, depending on such factors as snowlie, food supply (they eat mostly insects) and breeding success in previous years. Dotterel can lay in Scotland then lay a second clutch in Norway in the same season, and I once found a male on a nest in Scotland nine years after he had been ringed when breeding in Norway – by a study group I was with, possibly even by myself.
 
 
 
Tawny Frogmouth
These night-birds rely upon their cryptic colouring and behaviour to avoid 
daytime predators, and they are so difficult to find that there have been very few studies of them to date. I have identified over eighty breeding territories/pairs and followed their breeding success for several years. So far I have found that; birds in open woodland growing on moderately-rich soils live at higher density than those in close-canopy forest growing on poor soils; and they select to nest on branches which are orientated away from prevailing winds and exposed to more sunshine. This would allow them to have a more secure nest site and help the birds thermoregulate more efficiently. They are frequently seen basking in sunshine, especially in winter and this might be crucial behaviour for a species that likely evolved in a more tropical climate and now lives throughout temperate Australia too. Further long-term study of the population will focus on breeding behaviour and habitat use. 

 Birds and Windfarms
As many windfarms have been built and more proposed in the Scottish Highlands 
and Islands I have studied the behaviour of any birds which might be affected. These have included golden eagles, merlin, red kites, hen harriers, red-throated divers and waders such as golden plover greenshank. These studies have involved long periods of watching the birds’ behaviour, mapping their distribution, recording their flight heights and flight paths, monitoring their breeding success, and tracking them with radio-telemetry and satellite-tags . When all the information gathered from these studies is put together it is possible to determine just what parts of  a bird's home range they use most and least, allowing advice on where it would be best to place wind turbines and where they might cause disturbance. The success of such advice can then be measured with before and after results following post construction studies.
 

 Mink
Feral American mink are a predator which has greatly reduced the numbers and breeding 
success of ground-nesting birds, water birds and small mammals such as water voles. They became established throughout most of the UK following the escape and release of animals from fur-farms. In 1999 I made a baseline record of this effect for the Mink Eradication Scheme for the Hebrides. Arctic terns were the most affected species and no young were reared at 72% of their colonies. Other species affected were common tern, little tern and black-headed gull. Eradication of mink has been going on in the islands since then and there has been a great improvement in the breeding success of all these birds. Similar work has been done on parts of the mainland with rewarding success, particularly with water vole recovery.



Plant  Surveys
Plants are as much a part of my overall interest in arctic/alpine wildlife as birds. Indeed, the full understanding of how and why alpine animals live where they do cannot really be gained without a thorough knowledge of their use of different plants - a major feature of their habitat. I have 
made numerous surveys of vegetation and assessments of the condition of habitats in remote parts of the Highlands and Islands for Scottish Natural Heritage and on the high ground of Snowdon for the Countryside Council for Wales. From these and various other assessments of alpine vegetation throughout the country, it seems that for example, most of the decline in the Ptarmigan's range over the past century has probably been attributable to the loss of their food plants due to grazing by sheep and deer - the large numbers of which in the hills are an anthropogenic effect.


 Bird Ringing

Ringing, or banding as this is known in America and Australia, is an important method for studying birds. Small lightweight metal and sometimes also coloured plastic rings are put onto the birds’ legs with special pliers. Each metal ring is stamped with a unique alpha-numerical code and notification address. The plastic rings are applied in individual combinations of colours, or some are uniquely numbered/lettered. These methods allow the birds to be identified when subsequently seen, by which we can learn such details as where they move to and from, or how old they are. In recent studies of Greenshank in Scotland and Broad-billed Sandpipers in Norway, which I have worked on, we have also deployed geolocator tags which record details of time and day-length which allow calculation of the latitude and longitude of where the birds have been on migration. Conservation of any migratory species requires knowledge of its behaviour and habitat at both ends of its range.