Simms, E. (1952)
Bird Migrants:Some Aspects and Observations.
Cleaver-Hume Press, London, UK. pp.212 14 maps & diagrams 16 b&w photographs.
First published in 1952 this work is a useful possession for anyone with a serious interest in bird migration and of interest to any birder, particularly and perhaps somewhat unexpectedly, those living inland. Whilst much of the book has been rendered obsolete by subsequent works, most recently and notably Ian Newton’s superb New Naturalist title on Bird Migration, Simms study provides a useful historical context and his work on inland migration will be of great interest to devotees of visible migration. Simms opens by defining ‘typical’ migration as the ‘transfer of a breeding population’ from it’s summering to wintering grounds and compares this to other forms of movement such as partial migration, post-breeding dispersal, irruptions and accidental vagrancy. Brief outlines of migration patterns in different regions of the world follow. Bird migration throughout the year in the UK is then sketched out, starting in March, ending in February and using selected species to illustrate scenes familiar to any birder. Navigation is discussed, starting with methods used to ascertain the timing and direction of migratory movements and moving on to experimental work in which birds journeys are interrupted and the birds behaviour manipulated. Diurnal migration, the extent to which it is observable and nocturnal migration are then dealt with, the former being of particular interest to birders in the tricky business of trying to observe movements from the ground. This is followed by a chapter on movement on broad fronts and narrow routes. Simms proposes that the broad migratory front can be narrowed in places where a large number of birds follow a geographical feature such as a river valley, or where features such as hills cause a ‘deflection’ of the migratory stream. It has been argued that only the highest ground is likely to influence bird migration routes given the high altitude nature of most migratory flight. Simms himself is at pains to highlight the dangers of supposing narrow streams where none exist and certainly went to some trouble to check his own proposed narrowing of the broad front along the edge of the Cotswold range. It seems possible (to me at least) that migrants which crossed the North Sea overnight will be tired and looking for resting/foraging habitat by the time they reach the centre of the UK. Under such circumstances, hills may represent an obstacle which would be energy expensive to overcome leading to a path of least resistance along the lower contours. The next section of the book principally deals with Britain’s geographical location as a migratory hub and bird migration routes overland through the UK. These chapters on inland migration and the Cotswold Corridor are of great interest to anyone birding inland. In recent years the popularity of visible migration watching has soared in the UK, offering as it does, a very exciting opportunity for landlocked birders to do something completely different from the normal (and in my estimation, boring) trudge round a reservoir or gravel pit looking, predominantly, for waders and waterfowl. In Warwickshire several birders have been interested in visible migration watches for years now, inspired by Simms whose original observations, which led to the proposition of the Cotswold Corridor, were made in the county. Following up on Simms’s work, local birders have recorded many of the same species he did undertaking similar movements. Local rarities such as Rough-legged Buzzard (which Simms recorded), Black redstart and Ring Ouzel (which he didn’t) have also been found. You don’t have to go to localities Simms studied or even localities along routes he proposed, arguably the greatest value of this book to the modern reader is the inspiration to go out and look for your own watch-points and work out the significance and extent of the movements you observe. I was unable to find an ISBN number for this title but it is easy enough to find for sale on the internet for as little as 99 pence.