Rising global temperatures are causing a change to bird birthing rates across the globe, according to a new study carried out by James Cook University.
The research shows climbing temperatures have caused a decrease in birds being born, particularly for migratory species.
The birth rates of more than 56 per cent of birds worldwide was found to be declining, however there are some species of smaller birds that are thriving under the changes.
JCU researcher Dr. Martijn van de Pol says previous studies have shown how changes in temperature altered the timing of when birds breed.
“Global temperature has increased 1°C during the past 50 years.
“We systematically examined what this change means for the number of offspring produced.”
The global team of scientists, led by Dr Lucyna Halupka from the University of Wroclaw, examined breeding data for 201 populations of 104 bird species from around the world between 1970 to 2019.
JCU researcher Lyanne Brouwer says while more than 56 per cent of bird populations in the study showed a decline in offspring production, 44 per cent showed a positive trend.
“A decline was most common in migratory and large birds.
“However, other birds like small non-migratory species seem to benefit from global warming.
“Large species may be slower in responding to changing climatic conditions due to fact that they are long-lived, take several years to start breeding and produce small broods.
“Non-migratory species, especially smaller ones, are usually better able to adjust to changes in local conditions and may benefit from climate warming.”
The researchers say the declining birth rates can not fully explain why the vast majority of the bird species studied are declining in numbers, which suggests other causes for declines in avian biodiversity are also in play.
