Dr Nicholas Macgregor

Email: nicholas.macgregor at naturalengland.org.uk


Nick Macgregor is principal specialist in landscape scale adaptation at Natural England.
 
PhD Research
 
Despite much study of bird plumage colours, it is not clear why there is such diversity among bird species in the extent and pattern of sexual dichromatism and why dichromatic colours vary across species. I studied one particularly widespread colour scheme of dichromatism in passerine birds: black plumage in males and another colour, often brown or a similarly ‘dull’ colour, in females. I investigated a number of hypotheses relating to black plumage in males being a signal. Using a mixture of comparative analysis, experiments and observations in the field, I attempted to answer the following questions: Where on the body does sexually dichromatic black plumage most commonly occur? Is black plumage more conspicuous than brown plumage (the common female colour in these sexually dichromatic species) and is its conspicuousness influenced by microhabitat? Across species, is sexual dichromatism involving black male plumage associated with increased levels of competition between males and/or with particular types of habitat and light environment? Are differences in patterns of black plumage among males of related species consistent with the hypothesis that sexually dichromatic black plumage is a signal of species identity?

I found that sexually dichromatic black occurs most commonly on the head. Black appears to be more conspicuous, at least to predators and probably also to birds of the same species, than brown, and more conspicuous in microhabitats that have less foliage canopy overhead than in those under a denser canopy. There was no association between sexually dichromatic black plumage and the level of sexual size dimorphism (used as an indirect measure of the intensity of competition between males). I found an association between black plumage in males and relatively open habitat, though only in the ‘Passerida and allies’ group of passerines. However, a field study of 14 species of wood warblers (Parulini) found the opposite trend – males of species with larger amounts of black plumage sang from positions under denser canopy. I found a negative association between black dichromatism and male body size in some groups of passerines. Comparisons of congeneric species produced no evidence that patterns of sexually dichromatic black plumage have evolved to facilitate species recognition.

I try to continue this research in my spare time, when time permits.
Current work at DEFRA
 

My climate change work covers a range of aspects of adaptation (i.e. coping with the consequences of climate change). In particular it focuses on developing sustainable responses to climate change at a ‘landscape scale’ (i.e. over large geographic areas), incorporating natural ecosystems, human land use and agriculture and the interactions between them.
Among other things, this includes:

  • Developing methods for assessing the vulnerability of the natural environment to climate change;
  • Considering conservation strategies for a changing climate;
  • Reviewing past and current large scale conservation and adaptation initiatives;
  • Studying how natural ecosystems can benefit society and contribute to climate change adaptation and mitigation;
  • Developing approaches to climate risk assessment and sustainable adaptation;
  • Working on adaptation strategies for agricultural systems.

Nick Macgregor
 
PhD Research
Current work at Natural England
 
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, U. K.