When ringing birds it is usually important to standardise measurements so that sources of error are minimised. For example, trainee ringers are taught how to measure wing lengths in the most repeatable fashion. Measuring bird weight is usually much more straightforward. One situation where this may not be the case is during canon netting when large numbers of birds can be caught at once, but are weighed gradually as the birds are processed, potentially leading to biases. This paper examines this phenomenon using captures of Knot, Turnstone, Dunlin and Semipalmated Sandpiper in Delaware Bay, USA. As these waders were caught whilst actively feeding on the eggs of Horseshoe Crabs, there was the possibility that birds weighed first could be heavier due to having a gut full of eggs, whilst those weighed last may have digested/voided their gut contents prior to being weighed and so weigh relatively less. For sample bird catches birds were weighed repeatedly, from immediately after capture to up to four hours after capture. The study found that birds rapidly lost up to 5% of their body weight in the first 30 minutes, with weight loss much reduced thereafter. This weight loss was strongly correlated to the number of droppings birds produced in the keeping pens, indicating the reduction was related to processing of gut contents. The paper shows how body weights can be standardised to that expected if each bird was weighed at 30 minutes after capture. For large catches this can increase the apparent mean weight for the sample by up to 2%. The paper also discusses the situations in which standardising body weight measurements for time from capture may be necessary.

The stability of ecological communities has important consequences for the functioning of ecosystems, and several different mechanisms have been linked to delivering that stability. It has been shown, for example, that the stability of the species’ populations present within the community, together with the degree of synchrony that exists between them, can influence overall community stability. Larger populations tend to be more stable than smaller populations because they typically have greater genetic diversity and more capacity to adjust to environmental changes through natural selection, while populations situated closer to the middle of their preferred environmental niche tend to be more stable than those located at the margins. This study sought to identify which of these mechanisms was more important.

Many insect-eating birds are declining but it's hard to find data that can test whether insect declines are driving these losses. Understanding the relationships between insect populations, their avian predators and the effects of a changing climate, is an important part of identifying the reasons behind changes in bird populations. This paper uses nearly 30 years of data on aerial insect abundance and Swallow numbers and breeding success to explore these relationships.

The SHOT-SWITCH project was set up to monitor the effectiveness of voluntary initiatives to move away from the use of lead shot in game shooting. In the study’s third season, reported here, 94% of Pheasants sampled had been killed using lead ammunition, a slightly but significantly smaller proportion than in the preceding two seasons. There is currently no evidence that voluntary initiatives to promote the replacement of lead with non-lead ammunition by suppliers and retailers of wild-shot game are working.

The populations of many migrant birds have been in decline for decades, prompting research to understand the nature of these declines so that they can be addressed. The highly complex annual cycles of migrant birds, with their long migration routes and a dependence on different sites at different times of the year, makes it very difficult to identify the drivers of decline and to implement conservation action. While our knowledge is still incomplete, can we afford to wait until we have all of the answers?

This study identifies what could be a previously undetected biodiversity decline that potentially represents a significant conservation and economic issue in the UK.