Table 1 Summary of bird traits with explanation of the variable, season for which the trait was used (B = breeding, W = wintering), justification for its inclusion and source.
From: Different traits shape winners and losers in urban bird assemblages across seasons
Trait | Explanation | Season | Justification | Source |
|---|---|---|---|---|
Foraging strata generalism | Discrete (1 to 7: sum of the number of strata used by a given species. Categories: water below surface, water around surface, ground, understory, mid-high, canopy, aerial)—scaled | B, W | Three-dimensional use of the urban environment gives insights about the ability of a given species to use resources and exploit habitat structures | Wilman et al.62 |
Diet | Categorical (6 classes: granivore, herbivore aquatic, invertivore, vertivore, aquatic predator, omnivore) | B, W | Diet affects competition dynamics within an urban bird assemblage and is related to the habitat | Tobias et al.65 |
Migratory strategy | Categorical (3 classes: resident, short-distance migrant, long-distance migrant) | B, W | Migrants are associated with seasonal use of resources and higher specialisation which might be detrimental in an urban context | Tobias et al.65 |
Body mass | Continuous (grams)—scaled | B, W | Proxy of ecophysiological conditions, resource exploitation, life history and tolerance to disturbance and dispersal ability | Tobias et al.65 |
Life span | Continuous (years)—scaled | B, W | Longevity in birds is correlated with brain size, so it indirectly affects life-history and resource use | |
Fledgling period | Continuous (days)—scaled | B, W | Age at fledgeling reflects resource stability and colonisation ability in a urban context | Storchová and Hořák63 |
Nest type | Categorical (5 classes: ground, cavity, open, close to ground, closed-arboreal) | B, W | Nest site availability differs among urban habitats and affects predation exposure and inter-specific competition | Storchová and Hořák63 |
Association degree during nesting (ADN) | Categorical (3 classes: solitary, semi-colonial, colonial) | B | ADN has effects on predation exposure, interspecific competition, reproductive outcome and resource use during the breeding period | Storchová and Hořák63 |
Association degree outside the breeding nesting (AOBS) | Categorical (3 classes: gregarious, in pairs, solitary) | W | AOBS has effects on predation exposure, interspecific competition and resource use during winter | Storchová and Hořák63 |
Broods per year | Continuous (number of broods)—scaled | B, W | Number of broods per year is affected by phenology and resource seasonality and can be associated with urbanisation tolerance | Storchová and Hořák63 |
Clutch size | Continuous (number of eggs)—scaled | B, W | Clutch size evolved in response to environment and resource constraints and stability | Storchová and Hořák63 |
