Corridors, local food resources, and climatic conditions affect the utilization of the urban environment by the Black‐headed Gull Larus ridibundus in winter

Abstract

Black-headed Gulls Larus ridibundus (BHGs) in urban areas are a public nuisance. The aim of this study is to investigate the factors affecting the occurrence and abundance of the BHG foraging in urban areas in winter. The study was conducted in the city of Krakow (southern Poland) in four easily identifiable urban habitats: (1) areas with blocks of flats, (2) areas with congested housing, (3) detached single-family housing and (4) green areas. In each of these four habitats, 60 small (1-ha) plots were randomly chosen, and the bird's presence and abundance were noted. Results revealed that birds occurred most frequently and in the largest numbers in plots with blocks of flats and green areas as well as plots located close to rivers and water reservoirs. This highlights the importance of ecological corridors and stepping-stones for the presence of this species in the city. Food resources had no effect on the presence of the gulls but the abundance of the species was positively correlated with the number of litter-bins. This indicates that local food resources could be more important than large landfills for this species in urban habitats during winter. No human disturbance indices had an effect on the occurrence and abundance of the BHG. Higher temperature and lack of snow cover positively affected utilization of the urban habitats by the species that indicates that global warming may speed up synurbanization of the BHG. To control the number of BHGs in urban areas, we suggest preventing access to local food resources by placing litter bins with waste baskets that are inaccessible to animals. Also, the public should behave appropriately towards gulls and refrain from feeding them intentionally.

Food preference of the Black-headed GullChroicocephalus ridibundusdiffers along a rural–urban gradient

“…This increasing preference for anthropogenic food that Black-headed Gulls display as urbanicity increases, compares positively with previous studies of gulls (Raven & Coulson 1997, Auman et al 2008, Maciusik et al 2010, though ours is the first study to attempt to discern what the factors underlying this preference may be. Our results also demonstrated a difference in behavioural response to artificially provisioned foods along the urban-rural gradient suggesting that Blackheaded Gulls wintering along the Sefton Coast do not commonly move between habitats during the winter.…”

“…Gulls are a good example of this, and much research has been conducted suggesting that urban gulls are reliant on these food sources (Ewins et al 1994, Brousseau et al 1996, Belant et al 1998, Duhem et al 2003a, Duhem et al 2005, Kim & Monaghan 2006, Auman et al 2008. For example, Maciusik et al (2010) found that the abundance of the Black-headed Gull Chroicocephalus ridibundus, Linnaeus, 1766) in areas of Krakow, Poland, was positively correlated with the number of litter bins in that area. Despite anthropogenic food being found to be detrimental to many bird species (Belant et al 1998, Annett & Pierotti 1999, Boal & Mannan 1999, research has shown that anthropogenic food refuse can be beneficial to gulls in terms of their size and condition (Auman et al 2008) and reproductive success (Blount et al 2002, Duhem et al 2005.…”

Local and Landscape-Level Factors Affecting the Density and Distribution of the Feral PigeonColumba liviavar.domesticain an Urban Environment

“…Secondly, people often visit such places and frequently feed birds, especially in city parks. Elements of the original, pre-urban landscape, such as remnant forests or trees and open fields, together with lawns, weedy vegetation, and lower building density positively correlate to the abundance of many birds in towns (Chace & Walsh 2006, Maciusik et al 2010.…”

Landscape structure, human disturbance and crop management affect foraging ground selection by migrating geese

“…We distinguished between local roads and regional/national roads because the former are characterized by little traffic (usually much fewer than 100 vehicles per hour), whereas the latter represent roads with [500 vehicles per hour (authors' unpublished observations). Variables 14-15 may be indicators of the site's safety from predators, variables 16-17 describe the proximity of roosting areas or migration/dispersal corridors, as has been demonstrated for other waterbirds (Skórka et al 2009;Maciusik et al 2010). The lake size of 10 ha was chosen because it was the smallest lake where roosting geese were observed in the area (authors' unpublished observations).…”