Early arrival of spring due to warming climate disrupts breeding for birds, finds new study

As per the study, there is a mismatch between the start of spring and the readiness of the birds to reproduce. Due to the early onset of favourable weather, the birds start breeding too early or too late in the season, causing a dip in re-productivity.

The breeding season for birds typically begins when the first green plants and flowers appear after winter. This is now happening earlier as the climate warms leading to possible confusion for birds. Breeding season timing is significant for birds when it comes to raising the young.

If birds breed too early or too late, harsh weather could harm their eggs and further birds may find less food for their young before or after its natural availability.

“For nearly 30 years, scientists have hypothesised that animals could become mismatched from plants as springs begin earlier. While there have been a few very good case studies of this phenomenon, it has remained a major mystery whether advancing springs will pose a general problem for the majority of species,” said Morgan Tingley, a UCLA associate professor of ecology and evolutionary biology and the study's senior author, reported the Science Daily.

To investigate the theory, researchers took to a large-scale collaborative bird banding program run by the Institute for Bird Populations.

Using records, they calculated the timing of breeding and the number of young produced by 41 migratory and resident bird species of North America between the years 2001 and 2018.

Further, satellite imaging revealed the details of the places where vegetation began growing and where these birds are found.

In their analysis, scientists discovered that each species had an optimal time to breed which correlated to the number of young birds produced. Also, this number decreased when spring arrived very early, or if the birds began breeding early or too late.

The authors of the study have stressed conservation strategies to address the issue.