Constraints on home range behaviour affect nutritional condition in urban house sparrows (Passer domesticus)

Abstract

In human-dominated landscapes (semi)natural habitats are typically embedded in tracts of unsuitable habitat. Under such conditions, habitat characteristics and grain size of the surrounding landscape may affect how much food, and at what cost, is available for sedentary species with low home-range plasticity. Here we combine behavioural radio-tracking, feather ptilochronology, and landscape analysis to test how nutritional condition varies with home range size in 13 house sparrow [Passer domesticus (Linnaeus, 1758)] populations along an urban gradient. Urban individuals occupied smaller home ranges than conspecifics from rural areas, most distinctly if key cover was highly scattered. In urban plots, patch connectivity, home range sizes, and activity areas were positively correlated, indicating that individual ranging behaviour was related to the spatial distribution of suitable habitat. Urban House sparrows also showed the smallest feather growth bars, which were positively related to home range size at plot level. In contrast, growth bar widths and home range sizes were negatively related in rural populations, whereas in suburban populations, both variables varied independently. We conclude that individuals from progressively more built-up areas show a restricted ability to adjust their daily ranging behaviour to the scattered distribution of critical resources. This may complement other putative causes of the widespread population decline of urban house sparrows.

Testing assumptions of a supplementary feeding experiment aimed at suburban House SparrowsPasser domesticus

“…As most House Sparrows settle to breed within 1 km of their birth sites (Cheke 1972, Heij & Moeliker 1990, Anderson 2006) averaging only 0.21 km in Britain (Paradis et al 1998), and genetic mixing is particularly limited in suburban habitats (Vangestel et al 2010(Vangestel et al , 2011, natal dispersal between our study colonies was probably also minimal. Breeding dispersal in House Sparrows is even less pronounced than natal dispersal, averaging 0.15 km in Britain (Paradis et al 1998) and rarely exceeding 1-2 km (Summers-Smith 1988).…”

Differences in biometry and body condition of the House Sparrow (Passer domesticus) in urban and rural population during breeding season

“…This is partially consistent with literature data. For example, a decreased condition of the House Sparrows occupying urban and suburban territories was confirmed by ptilochronological data from Ghent, Belgium, compared to birds from rural areas (Vangestel et al 2010). Also Liker et al (2008) released data, obtained out of the breeding season and in a urbanization gradient, from the city center to rural areas in Hungary, that confirm the increase of adult bird condition, body mass and tarsus length but with no significant differences between sexes.…”

“…Liker et al (2008) suggest completing the credit card hypothesis by recognizing the influence of environmental impact on the development of hatchlings or even acknowledging it as a new alternative when explaining the weaker body condition of urban birds. Numerous studies confirm the lack of food typically found in the House sparrow's diet as a result of decreasing vegetation areas throughout cities accompanied by a plant management (Robinson et al 2005;Anderson 2006), habitat fragmentation (Vangestel et al 2010) and an increasing share of alien plant species (Marzluff 2001;Donnelly and Marzluff 2006). In addition, increasing levels of environmental pollutants, e.g.…”

“…As a factor of selection, urbanization may also lead to evolutionary changes in population's adaptation (Rodewald and Shustack 2008;Chamberlain et al 2009b;Rodewald et al 2014), especially as a response of individual avian species being dependent on the local ecological mechanisms (Rodewald 2012). A new adaptive response of potential preys linked with avoidance of predation risk can lead to changes in their body size and condition (Cresswell 2008;Vangestel et al 2010).…”

Effects of testosterone on the spatial ecology, coloration, and brain regions in western fence lizards, Sceloporus occidentalis

“…With decreased body condition, individuals would likely be in a negative energy balance and therefore be less likely to be able to maintain a larger home range size. Indeed body condition correlates positively with dispersal distance in Roe deer (Capreolus capreolus) (Debeffe et al, 2012), migratory distance in spawning herring (Clupea pallasii) (Slotte, 1999), and home range size in urban house sparrows (Passer domesticus) (Vangestel et al 2008). The negative effect of T and body condition could explain the lack of correlation of home range and cortical brain volume ranges.…”