Date: 3/2/17 10:39 am From: Philip C Stouffer <pstouffer...> Subject: [LABIRD-L] FW: [LABIRD-L] LALIT: Do bird feeders increase nest predation?
There have been a couple of recent papers on feeders in Ornithological Applications (=Condor).
This one is just out. The upshot is that when supplemental food attracts crows (not sure exactly how that works- it can't be a direct effect) it is bad for robin nest survival. Cardinals, on the other hand, don't seem to be affected.
http://www.americanornithologypubs.org/doi/abs/10.1650/CONDOR-16-72.1 - open access On that Ibis paper, I'd be hesitant to accept that predation on quail eggs in artificial nests reflects reality except perhaps in a loose qualitative way.
Back to the Red-headed Woodpecker thread, my impression is that the increase in Cooper's Hawks in LA is as Van described, a mostly urban/suburban phenomenon. Are Red-headed Woodpeckers declining in these settings? In my neighborhood in BR they are around (as are increasing coops). Is there anything in particular about rhwo that makes them vulnerable to coops? When I first got to LA I was impressed by rhwo drilling into creosote-coated poles. Maybe that habit of perching on poles (more than red-bellied, for instance) makes them easy prey?
From: Bulletin Board for Dissemination of Information on Louisiana Birds [mailto:<LABIRD-L...>] On Behalf Of Bill Vermillion
Sent: Thursday, March 02, 2017 9:37 AM
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.