The Bird Assemblage of the Darwin Region (Australia): What Is the Effect of Twenty Years of Increasing Urbanisation?

There has been considerable urban development in the Darwin region over the last twenty years; as for most fauna in Australia since colonisation, the potential effects to the bird assemblage were expected to be disastrous. To provide a broad overview of changes, bird survey data from 1998 and 2018 were extracted from BirdLife Australia’s ‘Atlas of Australian Birds’ database. A total of 165 species were categorised into primary food source feeding guilds and levels of food specialisation. This was integrated into ArcGIS along with land use change mapping from 1998 and 2018 to investigate its impact on bird assemblages. There was no significant change in overall species numbers when all sites were analysed. However, when sites were separated into those with increased urbanisation or decreased greenspace, several sites showed a significant change in the number of species. For the majority of species, analysis of primary food types found no difference in the proportion of species within the assemblages between 1998 and 2018, regardless of the level of urbanisation or greenspace; the exception being those species that primarily feed on insects, where the difference was just significant. An analysis using bird community data sorted into levels of food specialisation also found no difference between 1998 and 2018 despite habitat changes. These findings suggest that although there has been considerable urban development in the Darwin region, bird communities are remaining relatively stable.

Wetland birds in the northern prairie pothole region may show sensitivity to agriculture

Wetland losses in the Northern Prairie Pothole Region (NPPR) are largely attributed to agriculture. Since land-use is known to influence bird habitat selection, bird community composition is likely sensitive to the extent of neighboring agricultural activity. We determined which local and landscape habitat variables are most predictive of wetland bird assemblage occurrence in southern Alberta. We:1) identified distinct bird assemblages with a cluster analysis, 2) identified which species were indicative of these assemblages using an indicator species analysis and 3) predicted which bird assemblage would occur in a wetland with a classification and regression tree. Avian assemblages were more loosely defined and had few indicator species. Importantly, assemblages were specific to the natural region in which the wetland occurred. Also, landscapes with higher agricultural activity generally supported waterfowl and shorebirds, likely because agricultural activities excluded wetland-dependent birds that nest in upland habitat. Though waterfowl and shorebirds show poor sensitivity to surrounding landscape composition, edge-nesting wetland avifauna may make good indicators of ecological integrity.

Interannual dynamics of breeding bird assemblage within the Central Botanical Garden of the National Academy of Sciences of Belarus (Minsk)

We studied the dynamics of the composition and diversity of breeding bird assemblage within the Central Botanical Garden of the National Academy of Sciences of Belarus in Minsk during 2016–2019 and compared with census data from breeding seasons of 1982–1985 and 1991–1992. Total 86 species were recorded and the breeding was confirmed for 59 of them. The interannual dynamics of breeding density for 42 species is analysed. Overall bird densities varied from 2.03 pairs/ha to 8.76 pairs/ha during single year; 16 species (Fringilla coelebs, Erithacus rubecula, Turdus merula, T. philomelos, T. pilaris, Parus major, Cyanistes caeruleus, Sylvia atricapilla, S. borin, S. curruca, Phylloscopus sibilatrix, Ph. collybita, Ph. trochilus, Sturnus vulgaris, Pica pica and Columba palumbus) were shown to be the dominants in assemblage during these years. We found that there was increased in species richness (17 new breeding species appeared, 2 breeding species disappeared) and the overall breeding bird density (by almost 3– 4 times) since 1982. The main factors explaining the dynamics of some assemblage characteristics such as synurbization of some bird species and change in habitat structure are discussed.