Common Pochard sex ratio assessment
With estimated populations of 600,000 birds in Central Europe, Black Sea and Mediterranean and 250,000 birds in Northeast/Northwest Europe, the Common Pochard remains a familiar species to many waterbird counters and bird watchers across Europe and North Africa. However, there is growing concern over its conservation status. Now listed as Vulnerable on the European Red List of Birds and the global IUCN Red List, numbers have been falling in both European populations, which must mean either survival or productivity is decreasing (i.e. more birds are dying or fewer young are being produced). In order to improve our knowledge of the population structure of Common Pochard, the DSG is undertaking an assessment of the sex ratio of both European populations in January 2016.
It is well known that many wintering duck flocks exhibit considerable differences in overall sex ratio and that a greater proportion of the males are found north. Males are dominant over females and are therefore able to occupy more favourable wintering areas closer to the breeding grounds, forcing the sub-dominant females to move further afield. Males also migrate away from the breeding areas before the females, giving them a further head start. Partly as a result of the females’ more strenuous migration, and also their increased level of predation during the incubation period, the sex ratio in the population is typically biased towards males even though sex ratios are near unity at hatching.
The collection of sex ratio data can provide useful information on the population structure and even a crude assessment of relative changes in survival rates between the sexes. As many European duck populations are undergoing rapid changes in distribution and/or numbers, and little is known about their population demographics, it would be advantageous to start the collection of sex ratio data across Europe, which can be easily recorded for most species during standard waterbird counts.
During January 2016 we are seeking participation from waterbird counters and bird watchers across Europe and North Africa to help collect sex ratio data for Common Pochard. We are asking counters to simply record the number of males and females in flocks. This can be carried out as part of the next International Waterbird Census (16th/17th January 2016) or, if preferable, during a separate visit some other time in January 2016. We also welcome sex ratio counts from bird watchers who may happen to see Pochard flocks whilst out bird watching. The sex of every single bird in the flock is not required; however, please do try to obtain as large a sample as possible. The main data collection period for this assessment is taking place in January 2016, however we do also welcome sex ratio data throughout the winter too.
- The total flock size
- Number of birds assessed
- Number of males
- Number of females
|Total flock size||Number of birds assessed||Number of males||Number of females|
It is important we collect data from a good selection of habitats and different flock sizes as males tend to predominate at the best quality sites. Although more time is needed to record the sex ratio of large flocks, it is important for this project to get these data so please do try to at least sample large flocks at your sites. If you know of sites holding Common Pochard that are not routinely counted as part of a national waterbird count scheme it would be great if you could try and also visit them during January to collect sex ratio data (and please count all the other waterbirds too if you can!). Sex ratio data can be submitted using an online recording form which can be accessed below. However, if your national waterbird count scheme already has a system in place to collect sex ratio data, please submit your data there in the normal way as we can access it via your national organiser.
CLICK HERE to submit your data
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Counts can also be submitted via Birdtrack – if using Birdtrack, please make sure that you provide a 6-digit grid reference and also provide information on the habitat type. It’s also important to record the total number of birds assessed (the total number of males & females combined) which can be entered in the comments section.
Postal: Monitoring Unit, WWT Slimbridge, Gloucestershire GL2 7BT, UK
Tel: +44(0) 1453 891272