Behavioural Responses to Climate Change
Climate Change and Behavioural Research
- Climate change is a major ecological challenge.
- Behavioral research can improve understanding of how organisms adapt to a rapidly changing world.
- Focus on behavioral mechanisms underlying responses of individuals, populations, and species.
Strategic Regulation of Energy Reserves: European Storm Petrel
- Smallest Atlantic seabird, highly oceanic, long-distance migrant, and long-lived.
- Body mass variation is >12% of mean body mass with large fluctuations between years.
- Mass changes are related to local Sea Surface Temperatures (SST).
- Strong time-lag: SST in April linked to storm petrel fat reserves in May/June, suggesting a link via climate's effect on food supply.
Identification of Storm Petrel Prey
- DNA analysis of storm petrel faeces to identify prey species.
- Prey includes Greater fork-beard (16%), Sardines (48%), Atlantic mackerel (24%), Horse-mackerel (8%).
- Diet varies between years; also includes isopods, terrestrial invertebrates and dolphin.
Foraging Behaviour and Ecosystem Changes
- Foraging behavior is studied to understand responses to climate-driven ecosystem changes.
- Strategic buffering against starvation and prey switching are observed.
Climate Change Impacts on Wetland Songbirds
- Case study: Reed, Sedge & Cetti's Warblers.
Key Questions
- How does temperature affect bird-food abundance & phenology?
- How does food availability affect breeding, migration, overwinter survival, and recruitment?
Seasonal Abundance of Wetland Invertebrates
- Substantial variations between years in timing & shape of peak abundance.
- Positive effect of temperature on invertebrate abundance.
Warbler Diet Analysis
- DNA analysis reveals different diets among warbler species (CW, RW, SW).
- General Diptera, Chironomids, and Spiders are among the prey items.
- Different diets may lead to different responses to climate change.
Food Supplementation Experiments
- Treatment territories given unlimited mealworms to compare with unmanipulated territories.
- Breeding parameters are compared between fed & unfed territories.
- Fuel deposition rate and fuel load monitored remotely.
Impact of Food Availability
- Earlier laying date in warm years when reed growth is earlier.
Impact on Incubation & Nest Survival
- Fed birds have higher nest survival due to shorter incubation and greater nest attentiveness & defence.
Impact on Chick Growth
- Fed chicks show greater nestling mass compared to unfed chicks.
Impact on Breeding Productivity
- Total 1st brood productivity (number of chicks) varies by year.
Fat as Fuel
- Birds build up fat reserves to fuel migration journeys.
Fuelling Strategy of Migrant Reed Warblers
- Climate-driven changes in food supplies affect fuelling decisions and migration timing.
Overwinter Survival
- African rainfall explains only -10% of variation in annual survival of reed warblers.
Sahel Food Availability
- Reed warblers survive overwinter in dry scrub habitats.
Sahel Body Condition
- Strategic buffering against starvation in poor foraging conditions is suggested.
Climate Warming Effects
- Increased food availability leads to behavioural changes.
- Higher breeding productivity and annual survival result in higher recruitment.
Impacts on Upland Songbirds: Northern Wheatear
- Simulating climate-driven increases in food availability has limited effect on chick provisioning and nest success.
- Fed pairs lay eggs earlier, leading to multiple broods and higher annual productivity.
Impact of Supplementary Feeding on Survival
- Minimal impact on nestlings, large impact on fledgling and adult survival.
Climate Warming and Population Growth
- Increased food availability leads to behavioural changes.
- Higher breeding productivity and survival result in higher recruitment.
- Territories: Unfed 0.93 (contracting), Fed 1.14 (expanding).
- Climate, food availability, and local weather influence behaviours.
- Behaviours affect survival, fecundity, and population change.
- Understanding behavioural mechanisms is important.