The population size of animals may change because of variation in the number of births or deaths, or because individuals move between populations. Understanding these "demographic rates" helps us determine why populations are changing and what actions may be effective in conserving or managing the population. BTO's Ringing and Nest Record Schemes enable us to measure the effects of changes at different points in the life cycle and so understand better the difficulties our bird populations face.
Do Marsh Tits modify their behaviour to reduce competition?
Competition between species has been put forward as a possible reason for the declines seen in some bird species, including Marsh Tit and Willow Tit, but confirming a causal link between competition...
Read the BTO's latest BirdTrends report
The BirdTrends 2022 report is a one-stop shop for authoritative information about the population status of the common breeding birds in the UK.
Curlew collaboration to boost breeding success
Research from BTO and the University of East Anglia reveals how land management can support the breeding success of this declining species.
A different approach could provide warning of avian influenza outbreaks
Although we lack complete understanding of the disease links between wild and captive bird populations, the pattern of HPAI emergence in captive poultry reflects the movements of migratory waterfowl...
Are the declines of birds and invertebrates linked by climate change?
Many of the detected effects of climate change on biodiversity have occurred through impacts on food chains. We know that many birds are insectivorous during the breeding season, and various studies...
While most individuals disperse over short distances, long-distance dispersal is prevalent in almost all European bird species
In a study conducted in collaboration with BTO, scientists estimated the dispersal patterns of 234 European bird species using data from the EURING (European Union for Bird Ringing) Databank of birds...
Research reveals why Willow Warblers breeding in different parts of Britain are affected by climate change in different ways.
Pied Flycatcher population trends are driven by factors acting during migration and in non-breeding areas, an area which needs to be prioritised for future research.
Tracking data allows researchers to monitor Curlew without disturbance during the breeding season
The Curlew is of significant conservation concern in the UK, but many questions still remain about their breeding behaviour. This is partially due to the species’ cryptic nature and sensitivity to...
How protected areas benefit rare and declining birds
Research using data from BTO surveys shows how protected areas are working for UK birds.
Goose and Swan Monitoring Programme
This project tracks the abundance and breeding success of the UK’s native geese and migratory swans through winter surveys.
Avoiding tunnel vision during a PhD
Sophie Bennett reflects on her recent three month placement at the BTO and the value of taking a step back from a PhD.
A tale of two warblers
Breeding Bird Survey (BBS) results show very different population trends for Willow Warbler and Chiffchaff - but what is driving this difference? BTO research reveals climate is key.
Utilising more data for better biodiversity assessments
From volunteer surveys to environmental DNA, how can we integrate the many different types of data to better understand birds?
BTO travels to Europe!
BTO travels to key conferences in Europe to share research and experience with colleagues from around the globe.
Using bird ringing data to help target conservation management
Amidst widespread declines, how can we ensure conservation is targeted and effective? Analysis of ringing data may be key to answering this question.
Warming temperatures drive at least half of the magnitude of long-term trait changes in European birds
Climate change is impacting wild populations, but its relative importance compared to other causes of change is still unclear. Many studies assume that changes in traits primarily reflect effects of...
Birds of Conservation Concern
Commonly referred to as the UK Red List for birds, the status of birds has now been reviewed five times, Covering the UK, Channel Islands and Isle of Man. The latest review was published in...
Assessing drivers of winter abundance change in Eurasian Curlews Numenius arquata in England and Wales
Individual Tree Pipits identified by song
Acoustic monitoring is shown to be a valuable non-intrusive method of identifying individual birds in this new research.
Long-term and large-scale multispecies dataset tracking population changes of common European breeding birds
BirdTrends 2020: Trends in numbers, breeding success and survival for UK breeding birds
The BTO's BirdTrends report is a one-stop shop for information about the population status of the common breeding birds of the wider UK countryside.
Citizen science reveals patterns in Pied Flycatcher breeding
New research uses data from BirdTrack and the Nest Record Scheme to investigate how adaptable breeding Pied Flycatchers are to a changing climate.
Carryover effects of long-distance avian migration are weaker than effects of breeding environment in a partially migratory bird
Strengthening the evidence base for temperature-mediated phenological asynchrony and its impacts
The earlier arrival of spring, measured by plants flowering, insects emerging, and the timing of egg laying and migrants arriving in birds, is one of the most obvious impacts of climate change on the...
BTO and COVID-19
BTO statement on participating in surveys during the Coronavirus pandemic (UPDATED 17.01.2022).