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Individual study: Supplementary feeding increases survival in some forest birds but not others in Ohio, USA

Published source details

Doherty P.F. & Grubb T.C. (2002) Survivorship of permanent-resident birds in a fragmented forested landscape. Ecology, 83, 844-857


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide supplementary food for woodpeckers to increase adult survival Bird Conservation

A replicated, controlled study in 54 woodlots and riparian corridors in an agricultural landscape in Ohio, USA, in the winters of 1995-9 (Doherty & Grubb 2002) found that 378 downy woodpeckers Picoides pubescens did not have higher survival rates in either woodlots or riparian strips provided with supplementary food, compared with unfed, control sites. The impact on three songbird species is discussed in ‘Provide supplementary food to increase adult survival – Songbirds’. Supplementary food consisted of sunflower seeds and suet provided in excess throughout winter.

 

Provide supplementary food for songbirds to increase adult survival Bird Conservation

A replicated, controlled study in 54 woodlots and riparian corridors in an agricultural landscape in Ohio, USA, in the winters of 1995-9 (Doherty & Grubb 2002) found 315 Carolina chickadees Parus carolinensis (also known as Poecile carolinensis) had significantly higher survival rates in riparian sites provided with supplementary food, compared to those in unfed control sites (50% survival for fed areas vs. 43% for controls). This effect was not found in 346 white-breasted nuthatches Sitta carolinensis or 529 tufted titmice Baelophus bicolor. Chickadees in large plots supplied with food also had higher survival than those in unfed large plots. There was no such difference in smaller plots and no significant differences in the other species studied. The impact of feeding on downy woodpeckers Picoides pubescens is discussed in ‘Provide supplementary food to increase adult survival – Woodpeckers’. Supplementary food consisted of sunflower seeds and suet provided in excess throughout winter.

 

Provide supplementary food for songbirds to increase adult survival Bird Conservation

Another analysis (Doherty & Grubb 2002) of the same data as Doherty & Grubb 2002 also examined nutritional condition, judged by the size of feather growth bars, and found that 37 Carolina chickadees Parus carolinensis (also known as Poecile carolinensis) living in large woodlots were in significantly better nutritional condition (judged by the size of feather growth bars) when provided with supplementary food, compared with unfed controls. There were no significant differences in smaller woodlots. White-breasted nuthatches Sitta carolinensis had lower growth rates when fed, compared with controls and there was no impact of feeding on 48 tufted titmice Baelophus bicolor. The impact of feeding on downy woodpeckers Picoides pubescens is discussed in ‘Provide supplementary food to increase adult survival – Woodpeckers’.