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More misses than matches in the phenological synchronicity of urban passerines?

Falck, Jacob (2019) BIOK01 20191
Degree Projects in Biology
Popular Abstract
Late to the Party—Phenological Mismatches in Passerines

Spring arrives earlier in the city than it does in the countryside. The buildings trap heat, and the lack of green spaces means there aren’t enough plants to cool down the air through evaporation. This is known as the Urban Heat-Island effect (UHI). In Malmö the temperature increase is modest—in fact, it’s just about 1 °C warmer than in Skrylle. But this is enough to radically alter the conditions for life in the urban environment. The earlier (and warmer) spring and summer means that urban trees will burst their buds at an earlier date. This shift in a basal trophic level has a cascading effect—it will, for instance, cause leaf-eating caterpillars to emerge earlier. The bugs... (More)
Late to the Party—Phenological Mismatches in Passerines

Spring arrives earlier in the city than it does in the countryside. The buildings trap heat, and the lack of green spaces means there aren’t enough plants to cool down the air through evaporation. This is known as the Urban Heat-Island effect (UHI). In Malmö the temperature increase is modest—in fact, it’s just about 1 °C warmer than in Skrylle. But this is enough to radically alter the conditions for life in the urban environment. The earlier (and warmer) spring and summer means that urban trees will burst their buds at an earlier date. This shift in a basal trophic level has a cascading effect—it will, for instance, cause leaf-eating caterpillars to emerge earlier. The bugs reach their peak in Malmö several days before they do in the rural counterpart, Skrylle.

The great tit (Parus major) and the blue tit (Cyanistes caeruleus) rely heavily on the peaks in caterpillar biomass. Studies have shown that the tits adjust their reproduction so that their hatchlings will be born during periods of high caterpillar availability. The hatchlings’ diet will consist of 75% of larvae, which are rich in fatty acids and important nutrients. Being numerous and short-lived, insects can adapt quickly to the increasingly warmer conditions in the cities. But can P. major and C. caeruleus in their turn adapt to the faster urban pace?

By collecting frass, or caterpillar poop, that falls from the trees, you can get a good estimate of when the caterpillar biomass peak happens. And by doing thousands of nest-checks in hundreds of nest-boxes you get a lot of data on the birds’ reproduction. And it turns out that P. major and C. caeruleus don’t do so well in the city. They produce smaller clutches and weaker fledglings than rural populations. Although not tested for certain, a mismatch in the synchronicity with the caterpillar biomass peak may explain some of the poor performance of the urban tits.

Bachelor’s thesis in Biology 15 credits 2019
Department of Biology, Lund University

Supervisor: Ass. Prof. Caroline Isaksson
Urban Ecology, Department of Biology (Less)
Please use this url to cite or link to this publication:
author
Falck, Jacob
supervisor
organization
course
BIOK01 20191
year
type
M2 - Bachelor Degree
subject
language
English
id
8990600
date added to LUP
2019-07-11 08:35:12
date last changed
2019-07-11 08:35:12
@misc{8990600,
  author       = {{Falck, Jacob}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{More misses than matches in the phenological synchronicity of urban passerines?}},
  year         = {{2019}},
}