Measuring insect poo to help investigate the impacts of climate change on woodland birds.
As I mentioned in my last blog, the breeding success of hole-nesting woodland birds such as Blue Tits and Pied Flycatchers is thought to be dependent on the short seasonal spike in availability of caterpillar prey. These bird species usually have one nest attempt each year and so need to correctly time breeding to ensure that when their young are hungriest (when they are about 10 days old) enough food is available for them. Heavier fledglings are more likely to survive to become breeding birds themselves. Although these birds are able to adjust slightly, by delaying incubation after clutch completion for example, just a few days too late, or too early, can make the difference between brood death and survival.
Monitoring birds' timing of breeding and nest outcome is relatively easy, especially in nest box populations like I am involved with. Regular box inspections enable accurate calculation of when first eggs are laid, clutch size, the condition of nestlings at fledging and the number that fledge. Across the UK many thousands of nests in boxes are monitored annually. Monitoring invertebrates is less easy and relatively few people do this, and fewer still do so alongside detailed studies of breeding birds. But it is possible to estimate how invertebrate abundance changes during the breeding season using pretty simple techniques. The project I am involved in, with Ken Smith (now retired form the RSPB) and the universities of Edinburgh and Exeter, is interested in invertebrate abundance and how this changes during the course of spring, and how availability and timing varies spatially across the UK and between years. To achieve this we are encouraging citizen scientists who already monitor woodland breeding birds to additionally monitor invertebrates. Linking bird and invertebrate data gets 'bird people' thinking beyond just birds and participating and contributing to very worthwhile and important research. ...continue reading "Woodland birds response to climatic change: part 2"