The January issue of IBIS is one of our biggest yet, containing a Review, seventeen Original Articles, four Short Communications and a Viewpoint.
Here are four of the many highlights in this issue.
A decadal review of urban ornithology and a prospectus for the future
In a thoughtful and far-ranging review, doyen of urban ornithology Professor John Marzluff of the University of Washington in Seattle assesses the current state of urban ornithology. He shows that studies of birds in urban environments have increased exponentially, and that while the focus of these studies remains rooted in northern latitudes, there is clear evidence that interest in urban ornithology is spreading to tropical regions. He provides evidence that urban ornithology is maturing as a discipline, with a move away from purely documentary accounts of the avifaunas of cities to a more hypothesis-driven approach to assessing the demographic and phenotypic responses of birds to urbanisation and to recognising the response of human city dwellers to their avian neighbours as a legitimate and worthwhile field of study. Professor Marzluff concludes by suggesting a number of future directions that urban ornithology may take, such as assessing how birds survive in urban environments with abundant predators and predicting how functional biotic homogenisation may influence the functioning of urban bird communities.
Stability in prey abundance may buffer Black Sparrowhawks Accipiter melanoleucus from health impacts of urbanization
Jessleena Suri, Petra Sumasgutner, Eleonore Hellard, Ann Koeslag & Arjun Amar
As if in response to John Marzluff’s call for a more holistic approach to urban ornithology, Jessleena Suri and colleagues from the University of Cape Town, South Africa, address the question of how Black Sparrowhawks have managed to colonise and thrive in the dense urban sprawl of Cape Town, and specifically how their health is affected by life in an urban environment. Using measures of physiological stress and parasite burden, they show that Black Sparrowhawk chicks in nests in urban environments are unaffected by the degree of urbanisation around them, and indeed have lower levels of disease transmitted by insect vectors in the most urbanised areas. The authors suggest that the ready availability of prey species in even the most urbanised parts of Cape Town buffers this top predator against the negative health impacts of city life.
Provision of supplementary food for wild birds may increase the risk of local nest predation
Hugh J. Hanmer, Rebecca L. Thomas & Mark D. E. Fellowes
Staying with the theme of urban ecology, Hugh Hamner and colleagues from the University of Reading, UK, assess whether feeding birds in gardens influences the predation rate of nests nearby. Noting that in some parts of the world, up to half of all households regularly provide food for birds in their gardens, and that this also attracts avian and mammalian nest predators, they predicted that nest predation would be higher near centres of food provision. Using artificial nests and an experimental design using both filled and empty feeders, the authors show that nest predation rates are indeed significantly higher near filled feeders than near empty feeders. This has profound implications for assessing the overall ecological effect of providing artificial food sources for birds.
Assessing the importance of artificial nest-sites in the population dynamics of endangered Northern Aplomado Falcons Falco femoralis septentrionalis in South Texas using stochastic simulation models
Christopher J. W. McClure, Benjamin P. Pauli,Brian Mutch & Paul Juergens
Building on the theme of the provision of artificial resources, Christopher McClure and colleagues at the Peregrine Fund and at Boise State University assess the success of providing artificial nest platforms to the reintroduced population of Aplomado Falcons in southern Texas, USA. Using stochastic simulation models, they show that the provision of such platforms has enabled the population to increase to its current level, something that would not have been possible in the absence of such platforms. The level of productivity that such platforms has made possible means that the number of birds will saturate the available habitat, and that any subsequent increase in breeding pairs will only be possible with the creation of further areas of suitable habitat. The study elegantly demonstrates the massive conservation gains that can be achieved by providing resources as simple and cost effective as nesting platforms.