Graham Martin and Steve Portugal recently visited Birdworld in Surrey to begin a ongoing collaboration with Duncan Boulton and his team there. Birdworld has over 100 bird species, including some rare and unusual species. The primary aim of the first visit was to measure the visual fields of Northern Bald Ibises Geronticus eremita. This study follows on from a seminar given recent at the Centre for Ornithology by Susan Cunningham from Massey University in New Zealand. Here research has focused on the presence and density of Herbst corpuscles, which are touch sensitive receptors located in the bills of certain bird species. Susan has demonstrated that aquatic feeding ibises have many more of these touch sensitive receptors in their beaks than terrestrial feeders. The aim of the present work is to look at the visual fields of terrestrial and aquatic feeding ibis species, to investigate whether their visual fields reflect their use of tactile, as opposed to visual, cues when foraging. Bald Ibises are terrestrial foragers and the aim now is to investigate visual fields in some of the more aquatic feeding ibises.
The visual fields of Blacksmith Plovers Vanellus armatus were also measured. This information adds to a database of visual fields that Graham has collected covering many orders of birds which differ in their foraging ecology. Future collaborative work with Birdworld will aim to investigate the visual fields of aquatic foraging ibises, spoonbills and toucans.
