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opencc-zeroNov 2021View details →

The impact of urbanization on body size of Barn Swallows Hirundo rustica gutturalis

Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and non-urban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain body size, but urbanization also leads to habitat fragmentation, which may favour increases in body mass when for instance it correlates with dispersal capacity. However, this apparent contradiction has rarely been studied. This is particularly evident in China where the urbanization process is currently occurring at an unprecedented scale. Moreover, no study has addressed this issue across large geographical areas encompassing locations in different climates. In this regard, Barn Swallows (Hirundo rustica) are a suitable model to study the impact of urbanization on wild animals because they are a widely distributed species tightly associated with humans. Here, we collected body mass and wing length data for 359 breeding individuals of Barn Swallow (H. r. gutturalis) from 128 sites showing different levels of urbanization around the whole China. Using a set of linear mixed-effects models, we assessed how urbanization and geography influenced body size measured using body mass, wing length and their regression residuals. Interestingly, we found that the impact of urbanization was sex-dependent, negatively affecting males' body mass, its regression residuals, and females' wing length. We also found that northern and western individuals were larger, regarding both body mass and wing length, than southern and eastern individuals. Females were heavier than males, yet males had slightly longer wings than females. Overall, our results showed that body mass of males was particularly sensitive trait to urbanization, latitude and longitude, while it only showed a weak response to latitude in females. Conversely, while wing length showed a similar geographical pattern, it was only affected by urbanization in the case of females. Further research is needed to determine if these phenotypic differences are associated with negative effects of urbanization or potential selective advantages.

opencc-zeroMay 2022View details →

High within-clutch repeatability of eggshell phenotype in Barn Swallows (Hirundo rustica erythrogaster) despite less maculated last-laid eggs

Ecological and life history variation and both interspecific and intraspecific brood parasitism contribute to diversity in egg phenotype within the same species. In this study, Barn Swallows (Hirundo rustica erythrogaster) laid eggs with high intraclutch repeatability in egg size, shape, and maculation. Despite this high intraclutch repeatability, last-laid eggs had consistently less of the eggshell covered in spots and fewer spots than earlier-laid eggs in the clutch. We examined sources of interclutch and intraclutch variation using both direct measurements and custom-software (SpotEgg, NaturePatternMatch) that provide detailed information on egg characteristics, especially maculation measures. In addition to our main findings, maculation on different sides of the egg was highly repeatable; however, only shape, proportion of the eggshell maculated, and average spot size were repeatable between first and replacement clutches. Low intraclutch variation in maculation could allow females to recognize their clutch and this may be adaptive for colonial nesting species, such as the Barn Swallow. Characterizing intraspecific variation in egg size, shape, and maculation is the first step in understanding whether intraclutch variation is low enough - and interclutch variation high enough – such that eggs could serve as identity signals.

opencc-zeroMay 2024View details →

Data from: Year-round carryover effects are driven by migration phenology for Hirundo rustica (Barn Swallow) wintering in West Africa

Recently, population declines have been reported for many migratory birds. Because of complex life cycles, determining the causes for such declines is often difficult. Thus, migratory birds are of special conservation interest. We studied the migratory behavior of barn swallows Hirundo rustica tagged with solar geolocators and determined carryover effects during the entire annual cycle from one breeding season to the next. We used a Partial Least Square Path Model (PLS-PM) to disentangle migratory and breeding events that occur in chronological order. In addition, we controlled for broad environmental conditions in the wintering grounds (NDVI and latitude) and the specific moulting habitat (δ13C). We did not find a carryover effect from reproduction investment in the attachment year to breeding success in the subsequent year. Individuals which invested more in reproduction departed earlier from the breeding colonies, but this in turn did not affect the onset of autumn migration. Thus, the pre-migratory period should be acting as a buffer stage counteracting any previous carryover effects from reproduction investment. On the other hand, we found a long-lasting domino effect from the onset of autumn migration to subsequent breeding success, consistent with the notion of a migratory race. Specifically, individuals which started earlier the autumn migration, arrived earlier to the wintering grounds, started earlier the spring migration, arrived earlier to the breeding colonies and had a higher breeding success. We highlight that the pre-migratory period (i.e., the time elapsed between departure from breeding areas and the onset of autumn migration) should be important for the lifecycle of migratory species, but it has been frequently overlooked.

Fig. 5 in The Migratory Fattening Of The Barn Swallow Hirundo Rustica In Hungary

Fig. 5. Daily average body mass for juvenile and adult Barn Swallows at Izsák between 2000–2002

Fig. 2 in The Migratory Fattening Of The Barn Swallow Hirundo Rustica In Hungary

Fig. 2. Differences in residuals from ANCOVA models between Ócsa and Izsák in 2002

Fig. 4 in The Migratory Fattening Of The Barn Swallow Hirundo Rustica In Hungary

Fig. 4. Differences in body mass of Barn Swallows between years at Izsák 2000–2002

Fig. 3 in The Migratory Fattening Of The Barn Swallow Hirundo Rustica In Hungary

Fig. 3. Daily average body mass for juvenile and adult Barn Swallows at Ócsa and Izsák in 2002

Fig. 1 in The Migratory Fattening Of The Barn Swallow Hirundo Rustica In Hungary

Fig. 1. Differences in body mass and fat score of Barn Swallows between Ócsa and Izsák in 2002