BTO, Migratory Birds and Climate Change

The BTO, Migratory Birds and Climate Change

Britain is a cross-roads for many bird populations, with birds, such as swallows and warblers, migrating here from Africa to breed in the summer, and others, such as geese and shorebirds, coming here for the winter from further north and east. Yet others pass though on their annual journey across the globe. Climate change has the potential to disrupt many of these journeys, and to impact on migratory wildlife in other ways. Because of the long-term data gathered by volunteers, many of the BTO’s monitoring schemes have shown the widespread impacts of climate change on Britain’s birds.

BirdTrack monitors early bird arrival
	As spring temperatures increase, many migrant birds are arriving on their breeding grounds earlier. The results of several studies investigating the arrival time of spring migrants suggests that birds are reaching their breeding grounds progressively earlier in the season as temperatures in these areas increase. .Early
arrival is necessary if birds are time things right to feed their young. Peaks in the availability of insects and other food sources are also happening earlier in the year and to an even greater degree. A migrant’s departure from Africa is not always affected by temperature, but sometimes by day length. It is therefore uncertain as to whether birds will be able to keep pace with climate change in the future. Online recording schemes such as BirdTrack can be used to systematically document the arrival of spring migrants to see whether they are keeping pace. To find out more, Click here


Waders move closer to their breeding grounds
	The UK hosts a spectacular number of waders in winter. These waders breed in the high Arctic and are attracted to the UK by relatively mild winters and large expanses of food rich mud. Many estuaries receive special protection because of the internationally important numbers of .waders
they host. In every winter month since 1960 thousands of volunteers have braved wind and weather to count ducks and waders on their local ponds, lakes and estuaries and contribute these counts to the Wetland Bird Survey. Such long-term datasets are indispensable for revealing the impacts of climate change. New research by the BTO reveals that an increasing proportion of waders are opting to over-winter on estuaries in the north and east of the UK, closer to their breeding grounds. On some western estuaries, like the Severn, numbers have declined so dramatically that internationally important numbers are no longer hosted. Could spectacular flocks of waders soon become a thing of the past? Ongoing BTO research shows that if this trend continues, they could leave the UK all together. Some species have shifted their range so dramatically that they now over-winter more than 100 miles northeast of where they did 20 years ago. To find out more, Click here

BTO Nest Record scheme shows that birds are nesting earlier
	The BTO Nest Record Scheme holds more than a million detailed records of individual nesting attempts for a large number of species, including many migrants, gathered over the whole country and collected by volunteer ornithologists from the 1930s onwards. it has provided some .of .the .strongest .evidence to .date .of
the broad-scale impact of climate change on wildlife. BTO research making use of this dataset, published in the prestigious scientific journal Nature, has shown that the majority (51 out of 65) species tended towards earlier nesting between 1971 and 1995. This work has since been followed this up by a study looking at a longer run of 57 years (1939-1995) of data and seeing how the changes are related to temperature and rainfall for 36 well-recorded species. A very clear pattern has emerged: most over half the species (19, or 53%) showed a pattern of early laying dates in the 1940s and 1950s, later laying dates in the 1960s and 1970s and then earlier laying dates again in the 1980s and 1990s. This pattern matches well with changes in average spring temperatures: these have become cooler and then warmer over the last half-century. To find out more, Click here


BTO Atlas reveals northward shift in breeding birds
	As temperatures warm many birds are shifting their breeding range northwards as conditions in more northerly areas become increasingly favourable in terms of weather and food availability. Research based on data collected for the BTO’s Bird Atlases and published in the prestigious scientific .journal. Nature, .has
shown that British bird species have extended their breeding ranges northward by 18.9 km in response to warmer temperatures. Many of these are migrant birds. To find out more, Click here

BTO takes the lead on climate change report
	A recent BTO lead research report for Defra showed the many ways in which migratory wildlife will be affected by climate change. Some of the world’s most spectacular migratory animals will be severely affected by climate change, with many types of animals retracting their range towards the poles. In the UK the incidence of
'southern' species such as the Little Egret, Loggerhead Turtle and Red Mullet is increasing. Climate change is also changing migration routes. Some European Blackcaps are now migrating west to Britain rather than south to Africa, and Chiffchaffs are remaining in the UK over winter (rather than migrating south). The act of migration itself may become more difficult due to climate change. For example, many migratory birds use the Sahel region of Africa to refuel before making the northerly crossing of the Sahara Desert. Decreased rainfall is causing increased desertification in this area, leading to declines in a number of species such as the Whitethroat. Further declines in trans-Saharan migrants might be expected with climate change. WE know most about birds however. Of the species evaluated, 84% face some threat from climate change, particularly from changes in water regimes. This is equivalent to the combined threat from all other human causes. This report was presented to the 8th Conference of the UN Convention on the Conservation of Migratory Species in Nairobi, 2006 and was instrumental in the Convention recognising the importance of climate change in conserving migratory wildlife. To find out more, Click here

Other interesting stories…
The value of long-term datasets Climate change causes birds to starve BTO research shows that bird survival is affected by climate change BTO research shows that UK migrants are affected by rainfall in Africa BTO to report on impacts of climate change on migratory waterbirds
To find out more details contact Paul Stancliffe or Ilya Maclean