A new Oxford University study recently revealed that shifts in the timing of "egg-laying by great tit birds" as a reaction to climate change differ evidently between breeding sites within the same woodland. Such a difference is associated with the tree health of nearby oaks.
Great tit birds in the United Kingdom, according to a Phys.org report, lay their eggs approximately 14 days earlier than they did during the 1960s decade.
Consequently, these songbirds keep pace with the other members of their food chain, which includes winter moth caterpillars and the oak trees on which such insects are feeding, which have advanced their spring timing as well, in response to climate change for the past several years.
Much of the insight into how animals respond to climate change comes from research assuming that all individuals within a populace are experiencing the same environment.
How Birds Deal with Climate Change
Nonetheless, it's known that this is not the case, specifically for animals that are restricted in terms of the distance they can travel from reliant offspring.
Neighboring individuals are likely to experience quite different environments. According to Oxford University's Dr. Ella Cole, who co-led the study, examining such differences helps understand what might restrict the animals' ability to adapt to changing environments and thus the scope of populations to deal with climate change.
This new research from the Department of Zoology, Oxford University, has shown marked spatial differences in the degree to which great tit birds adapt to their timing of laying eggs within a single woodland.
Examination of breeding events from more than 13,000 great tit birds, as described in the Garden Birds site over a six-decade period, showed that the slowest nesting areas have just advanced by 7.5 days, while the fastest areas advanced by 25.6 days.
Advancement in the Timing of Laying
The said difference is associated with the health of the oak trees close to the nesting site. The healthier these trees are surrounding the nest, the bigger the advancement in timing the birds' laying.
Breeding birds in sites that have healthy oaks advanced their laying 5.4 days more compared to those breeding in sites that have unhealthy oaks.
The study published in the Nature Climate Change journal presents how investigating responses to climate change at tiny spatial scales show patterns and associations that are masked by population-wide research.
The study, performed at the Wytham Woods of Oxford University, used breeding data from more than 960 fixed-location next boxes, along with information on the health of over 5,700 mature oak trees.
Essentiality of Oak Trees to Great Tit Birds
As specified in the study, oak trees are vital to great tit birds during the spring due to the large number of caterpillars feeding on their foliage.
It's known from past research that great tit birds that nest in territories that contain lots of oak trees start laying earlier "and are more successful breeders."
According to Oxford University's Dr. Regan, their study findings suggest that birds that nest in areas with poorer oak health have a lesser capability of keeping up with the advancement of spring.
This, he added, could be because they are not able to find the resources needed to begin breeding or because decreases in oak health impact the hints birds are using to time breeding.
Related information about the breeding process of great tit birds is shown on WH Amazing Animals' YouTube video below:
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