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Providing evidence to improve practice

Individual study: Supplementary food shows mixed effects on fledging success and survival in Florida scrub jays Aphelocoma coerulescens in scrubland in Florida, USA

Published source details

Reynolds S.J., Schoech S.J & Bowman R. (2003) Diet quality during pre-laying and nestling periods influences growth and survival of Florida scrub-jay (Aphelocoma coerulescens) chicks. Journal of Zoology, 261, 217-226

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Provide supplementary food for songbirds to increase reproductive success Bird Conservation

A randomised, replicated and controlled cross-over trial in a dune and scrubland system in Florida, USA, in 2000 and 2001 (Reynolds et al. 2003), found that that 21 female Florida scrub jays Aphelocoma coerulescens provided with high-fat, low-protein (HFLP) supplementary food and 21 females provided with high-fat, high-protein (HFHP) food laid significantly larger clutches than 55 control females in 2000 but not 2001 (2000: approximately 3.7 eggs/clutch for HFLP diets, 3.2 eggs/clutch for HFHP and 2.8 eggs/clutch for controls; 2001: 2.7 eggs/clutch, 3.1 eggs/clutch and 2.8 eggs/clutch respectively). This was due to earlier laying, discussed below. Clutches on the HFHP diet had a tendency to have larger third-laid eggs, but other eggs were not significantly different in size between treatments. Feeding began in early- or mid-January and continued until females began laying, usually six to eight weeks later. Food consisted of food pellets containing 19.3% fat and with a protein content of either 3.5% or 34.5%.