My research interests focus on how animals, specifically seabirds, adapt to their natural environment, both physiologically and behaviourally. The questions addressed thus far during my research have ranged from how macaroni penguins are able to dive for as deep and as long as we observe (Green et al. 2005b), to why albatross chicks of closely related species have different growth rates (Phillips et al. 2003). Such topics are of particular importance to seabirds as they adapt to new threats in their natural environment from sources such as over-fishing and climate change. 

Much of my work has utilized heart rate logging techniques. Heart rate can be recorded in free-ranging animals for periods of up to 15 months using miniature recording devices. Heart rate is a reliable indicator of energy expenditure and this relationship can be accurately quantified in laboratory experiments. As a result, temporally precise estimates can be made of the energetic cost of the full range of activities undertaken by free-ranging animals (Butler et al. 2004a, Green et al. 2002). As well as establishing such calibration relationships for the species I have studied (Green et al. 2001, Green et al. 2005a), I have attempted to further our understanding of the capacities and capabilities of this technique (Green et al. 2005e). I conducted my doctoral and first post doctoral work at the University of Birmingham on macaroni penguins with Pat Butler. Since then I have continued to collaborate with several members of the Centre for Ornithology as part of studies on barnacle geese (Butler, Portugal), little penguins (Butler, Frappell), domestic chickens (Halsey, Frappell), Australasian gannets (Butler, Frappell) and great cormorants (Butler, White, Martin, Gremillet).

Recent Publications:

Green, J.A., Halsey L.G., Wilson, R.P. & Frappell, P.B. (2009) Estimating energy expenditure of animals using the accelerometry technique: activity, inactivity and comparison to the heart rate technique. Journal of Experimental Biology. 212, 471-482 http://dx.doi.org/10.1242/jeb.026377

Green, J.A., Frappell, P.B., Clark, T.D. & Butler, P.J. (2008) Predicting rate of oxygen consumption from heart rate while little penguins work rest and play. Comparative Biochemistry and Physiology Part A. 150, 222-230 http://dx.doi.org/10.1016/j.cbpa.2006.06.017

Green, J.A., Boyd, I.L., Woakes, A.J., Green C.J. & Butler, P.J. (2007) Feeding, fasting and foraging success during chick-rearing in macaroni penguins. Marine Ecology Progress Series. 346, 299-312 http://dx.doi.org/10.3354/meps07024