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Sam's research focuses on the interface between competition and physiology in tropical birds. Specifically, he is interested in two principle themes: how physiology and interspecific competition may combine to predict avian range patterns, and the energetic costs of territorial competition.

Physiology and competition in elevational range patterns

Species communities on tropical mountains are typified by ‘elevational turnover’, where related species replace one another at different elevations, often occupying elevational ranges spanning just a few hundred metres. Three particular factors have been suggested as the main drivers of such patterns- changing ecotones (habitat transitions), physiological tolerance (the upper and lower temperature limits in which a species can physically survive) and competition (where interspecific aggression at shared distributional boundaries restricts elevational ranges). The relationship between each of these factors remains unclear, however.

Energetics and competition

The ‘pace of life’ in tropical birds is known to be slower than temperate species in that tropical species typically have lower metabolic rates. Additionally, the relatively constant conditions in tropical forests allows for extended breeding seasons where sedentary lifestyles and year-round territoriality are common. How this ‘pace of life’ translates into the behavioural energetics of territorial competition in tropical birds remains little known. More broadly, the physiological ecology of tropical birds remains poorly-known despite key life-history differences to temperate species.

To investigate these topics, Sam studies songbirds of the forest understorey, particularly Nightingale-thrushes (Catharus sp.) in Central America. His research is fieldwork-based and takes place in the montane forests of Cusuco national park, Honduras.

Additionally, he has strong interests in the general natural history and ecology of birds, particularly in poorly studied regions of the tropics.


  • –present
    Postgraduate researcher in Ornithology, Royal Holloway