Avian migration strategies may include intra-specific variations, also known as differential migration. These migratory adaptations between conspecifics are particularly important given their implications for population dynamics. We aimed to examine the differential migration pattern as a function of age and sex, and whether this pattern also determines body morphology, in a passerine whose migration strategy includes movements to both pre- and sub-Saharan wintering areas. Thus, 1,100 common chiffchaffs Phylloscopus collybita were sampled during 2009–2012 at eight wintering locations within the Palearctic and Afrotropical regions. Biometric and body condition variables were studied for their relationship to geographical, climatic and productivity indexes. A higher proportion of adults and females were observed at lower latitudes. Common chiffchaffs were larger and in better body condition in sub-Saharan areas, coinciding with greater plant productivity and less annual rainfall. The selection of the southernmost areas by adults may be related to fidelity to more favourable sites. Southern and coastal locations offer better conditions for chiffchaffs, despite the challenges involved in crossing the Sahara Desert. Moreover, the greater skills of adults in finding abundant food resources may also drive greater relative abundance south of the Sahara. Greater body mass and fat deposits in birds wintering in sub-Saharan areas reflect higher resource availability and may imply that the birds are in better physical condition.

This is the third edition of the Northern Ireland Seabird Report, covering 2015. This report is the published outcome of the work of the British Trust for Ornithology (BTO) Seabird Coordinator, appointed in February 2013, and the activities of the evolving Northern Ireland Seabird Network of volunteers, and organisations such as National Trust, Ulster Wildlife and the RSPB that have provided data for 2015 and previous years. The report on breeding seabirds in Northern Ireland during 2015 presented here is similar to 2013 and 2014. We have kept the detail from previous years, even where data have changed little since our last report. It is important that this report represents a summary of current species knowledge, and that reference to other, earlier, reports is not necessary. In this we are taking a similar stance to JNCC and their online SMP report and this is doubtless the best way to present such a report. As in previous years a number of articles have been submitted for inclusion in the Northern Ireland Seabird Report. These articles provide further detail on the monitoring in Northern Ireland, and highlight some of the exciting seabird research being undertaken. We are very grateful to the authors for giving their time to produce these articles.

This is the second edition of the Northern Ireland Seabird Report, covering 2014. This report is the published outcome of the work of the British Trust for Ornithology (BTO) Seabird Co-ordinator, appointed in February 2013, and the activities of the evolving Northern Ireland Seabird Network of volunteers, and organisations such as National Trust, Ulster Wildlife and the Royal Society for the Protection of Birds (RSPB) that have provided data for 2014 and previous years. Interest in Northern Ireland’s marine environment continues to grow. The process of designating Marine Conservation Zones in Northern Ireland waters is ongoing, and there is considerable effort being put into consideration of a number of SPA extensions. Despite the recent withdrawal of proposals for the development of an offshore wind farm off the Co. Down coast, there are many other developments being considered in Northern Ireland’s marine environment. Designations and planning consents all require high quality marine biodiversity data of various types, including for birds. At the core of the Seabird Network in Northern Ireland are our surveyors. Some work for Government bodies such as NIEA, while others survey on behalf of NGOs such as RSPB, Ulster Wildlife and the National Trust. We are grateful for their co-operation and assistance. Many other surveyors are volunteers who give up their time freely to help, simply because of a love and admiration of these bird species. The amount and quality of work that can be undertaken by volunteers is amazing and in 2014 we were fortunate that many new and enthusiastic people joined the already talented Seabird Network. The Seabird Network now numbers 60 people, a great achievement when there were only 20 people in Northern Ireland surveying seabirds just two years ago. The report on breeding seabirds in Northern Ireland during 2014 presented here is similar to 2013. We have kept the detail from previous years, even where data have changed little since our last report. It is important that this report represents a summary of current species knowledge, and that reference to other, earlier, reports is not necessary. In this we are taking a similar stance to JNCC and their online SMP report and this is doubtless the best way to present such a report.

Data from the Wetland Bird Survey have contributed to new research showing how Europe's winter population of Smew has redistributed north-eastwards due to milder winter conditions in the last 25 years. The study, involving scientists in 16 countries, also demonstrated that population growth has been twice as fast inside protected areas compared to outside. Many bird species are showing distributional change in response to global warming. New research using data collected by volunteers taking part in the Wetland Bird Survey shows that Europe's winter population of Smew has redistributed north-eastwards due to milder winter conditions in the last 25 years. In the UK, a small population of typically less than 200 Smew (and in mild winters just a few dozen birds) can be found in winter at favoured gravel pits and reservoirs in lowland England. This UK population has approximately halved since the late 1990s. This study, compiled by scientists in 16 countries (including BTO staff) shows that Special Protection Areas (SPAs) scheduled under the EU Birds Directive, facilitate such distribution change across a species’ entire range. Currently, one third of the total population winters in north-eastern Europe, compared to 6% two decades ago. Furthermore, population growth rate in this region was also twice as fast inside EU Birds Directive’s SPAs compared to those outside over the last 25 years. Thus, well designed protected area networks can mitigate the effects of climate change on biodiversity by safeguarding high quality habitat as species adopt new distributions. These findings confirm that the existence of Special Protection Areas assists species to cope with climate change. However, the results also highlighted severe gaps in the EU Special protection Area network, especially in northern parts of the wintering range. Many countries designated their SPAs more than 20 years ago, when no account was taken of the rapid environmental changes now occurring. More than eight out of ten Smew wintering in Latvia and Sweden do so in currently unprotected areas, and in Finland nearly all individuals winter outside the SPA network. Despite this range shift, it is still important to maintain the network at the southern end of the birds’ range, so that they have somewhere to retreat during particularly harsh winters. Studies such as this can help policy makers review protected area networks to ensure they keep pace with the conservation needs of Smew and other species.