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Effects of interspecific coexistence on laying date and clutch size in two closely related species of hole‐nesting birds
Author(s) -
Møller Anders Pape,
Balbontín Javier,
Dhondt André A.,
Remeš Vladimir,
Adriaensen Frank,
Biard Clotilde,
Camprodon Jordi,
Cichoń Mariusz,
Doligez Blandine,
Dubiec Anna,
Eens Marcel,
Eeva Tapio,
Goodenough Anne E.,
Gosler Andrew G.,
Gustafsson Lars,
Heeb Philipp,
Hinsley Shelley A.,
Jacob Staffan,
Juškaitis Rimvydas,
Laaksonen Toni,
Leclercq Bernard,
Massa Bruno,
Mazgajski Tomasz D.,
Nager Ruedi G.,
Nilsson JanÅke,
Nilsson Sven G.,
Norte Ana C.,
Pinxten Rianne,
Robles Hugo,
Solonen Tapio,
Sorace Alberto,
van Noordwijk Arie J.,
Lambrechts Marcel M.
Publication year - 2018
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/1365-2656.12896
Subject(s) - interspecific competition , intraspecific competition , avian clutch size , biology , competition (biology) , parus , ecology , storage effect , cyanistes , range (aeronautics) , nest (protein structural motif) , zoology , reproduction , biochemistry , materials science , composite material
Coexistence between great tits Parus major and blue tits Cyanistes caeruleus , but also other hole‐nesting taxa, constitutes a classic example of species co‐occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variations in coexistence and its consequences for competition remain poorly understood. We used an extensive database on reproduction in nest boxes by great and blue tits based on 87 study plots across Europe and Northern Africa during 1957–2012 for a total of 19,075 great tit and 16,729 blue tit clutches to assess correlative evidence for a relationship between laying date and clutch size, respectively, and density consistent with effects of intraspecific and interspecific competition. In an initial set of analyses, we statistically controlled for a suite of site‐specific variables. We found evidence for an effect of intraspecific competition on blue tit laying date (later laying at higher density) and clutch size (smaller clutch size at higher density), but no evidence of significant effects of intraspecific competition in great tits, nor effects of interspecific competition for either species. To further control for site‐specific variation caused by a range of potentially confounding variables, we compared means and variances in laying date and clutch size of great and blue tits among three categories of difference in density between the two species. We exploited the fact that means and variances are generally positively correlated. If interspecific competition occurs, we predicted a reduction in mean and an increase in variance in clutch size in great tit and blue tit when density of heterospecifics is higher than the density of conspecifics, and for intraspecific competition, this reduction would occur when density of conspecifics is higher than the density of heterospecifics. Such comparisons of temporal patterns of means and variances revealed evidence, for both species, consistent with intraspecific competition and to a smaller extent with interspecific competition. These findings suggest that competition associated with reproductive behaviour between blue and great tits is widespread, but also varies across large spatial and temporal scales.