Date: 3/2/17 7:51 am From: Bill Vermillion <bill.gcjv...> Subject: [LABIRD-L] LALIT: Do bird feeders increase nest predation?
I was sent a 2016 paper from the journal Ibis this past week which
documents research in the United Kingdom investigating whether bird feeding
increases risk of nest predation for birds nesting in relatively close
proximity to bird feeders. Researchers deployed filled and un-filled
feeders and deployed artificial nests with Japanese quail eggs. Predation
of these artificial nests by Magpies, Gray Squirrels, and European Jays was
significantly higher adjacent to filled feeders.
Here's the citation and abstract:
Hanmer, H.J., R.L. Thomas, and M.D.E. Fellows. 2016. Provision of
supplementary food for wild birds may increase the risk of local nest
predation. Ibis 159:158-167.
Abstract: In countries such as the UK, USA and Australia, approximately
half of all households provide supplementary food for wild birds, making
this the public’s most common form of active engagement with nature.
Year-round supplementary feeding is currently encouraged by major
conservation charities in the UK as it is thought to be of benefit to bird
conservation. However, little is understood about how the provision of
supplementary food affects the behaviour and ecology of target and
non-target species. Given the scale of supplementary feeding, any negative
effects may have important implications for conservation. Potential nest
predators are abundant in urban areas and some species frequently visit
supplementary feeding stations. We assess whether providing supplementary
food affects the likelihood of nest predation in the vicinity of the
feeder, by acting as a point attractant for potential nest predators. We
provided feeding stations (empty, peanut feeder, peanut feeder with guard
to exclude potential nest predators) in an area of suburban parkland in the
UK and monitored the predation rate of eggs placed in arti- ficial nests
located at distances that replicated the size of typical suburban gardens.
Nest predators (Magpies Pica pica, Grey Squirrels Sciurus carolinensis)
were frequent visitors to filled feeders, and predation caused by Magpies,
European Jays Garrulus glandarius and Grey Squirrels was significantly
higher when nests were adjacent to filled feeders. The presence of a feeder
guard did not significantly reduce nest predation. As supplementary feeding
is becoming increasingly common during the breeding season in suburban
habitats, we suggest that providing point attractants to nest predators at
this time may have previously unconsidered consequences for the breeding
success of urban birds.