Urban bird trends in a rapidly growing tropical city

Chamberlain, Dan; Kibuule, Micheal; Skeen, Roger Q.; Pomeroy, Derek

doi:10.2989/00306525.2018.1489908

Cited by 16 publications

(14 citation statements)

References 36 publications

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“…This is most obvious in the scavenger guild, where almost all vultures (except the Hooded Vulture) are rarely recorded in urban environments, but these species have been replaced by large numbers of a few common scavenger species: Pied Crow and Marabou Stork, and Sacred Ibis Threskiornis aethiopicus to a lesser degree. Similar to the findings of Chamberlain et al (2018) from Uganda, generalist scavengers appear to be benefiting across the continent, whereas some insectivores are declining, although notable exceptions appear to include Fork-tailed Drongo Dicrurus adsimilis and Little Swift. However, for all of these guilds, as well as frugivores, there are large numbers of common species, such as Laughing Dove and Red-eyed Dove, making up for loss of specialists.…”

Section: Functional Diversity and Dietary Guildssupporting

confidence: 62%

“…This feeds into the globally observed trend of a decline in species diversity as the amount of urban land cover increases across landscapes (Batáry et al 2018). This general pattern is also seen in bird communities of developing countries (van Rensburg et al 2009;MacGregor-Fors and Schondube 2011;Silva et al 2015;Chamberlain et al 2018), although some notable exceptions arise depending on the quality of the surrounding natural (rural) vegetation type and water availability (Dures and Cumming 2010;Chamberlain et al 2020). Unfortunately, it is difficult to ascribe causality to the variety of different ecological and environmental factors that are affecting bird diversity across our urbanrural gradient.…”

Section: Species Richness and Diversitymentioning

confidence: 91%

“…Our findings generally conform to earlier results suggesting that urban exploiting birds are generalists (Evans et al 2011), with the implication that habitat specialists in proximity to expanding cities will require conservation attention. However, of note is that the African urban bird is more likely to be described by scavenging dietary habits, revealing the unique foraging niche available across the African continent and commented on before by Chamberlain et al (2018). McPherson et al (2021) also noted that urban raptors are best described by a scavenging diet.…”

Section: What Makes An African Urban Bird?mentioning

confidence: 99%

“…Across Africa, how bird species are responding to urbanisation and associated threats and opportunities, is very mixed: population declines for Hooded Vulture Necrosyrtes monachus (Mullié et al 2017), dietary adaptation for Crowned Eagle Stephanoaetus coronatus (McPherson et al 2015;van der Meer et al 2018), earlier breeding for Marabou Stork Leptoptilos crumenifer (Pomeroy and Kibuule 2017) and Peregrine Falcon Falco peregrinus (Sumasgutner et al 2020) and facilitation of the alien urban invader the Indian House Crow Corvus splendens (Shimba and Jonah 2017), are some examples of the numerous varied responses. Additionally, Chamberlain et al (2018) showed long-term changes in bird functional feeding guilds in response to an urban gradient in Kampala, Uganda, where insectivores and granivores were found to have declined, whereas the most common predators and scavengers benefitted from the inability of municipal waste management to keep pace with growth from the human population, hence providing more potential food resources.…”

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confidence: 99%

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Urban areas have lower species richness, but maintain functional diversity: insights from the African Bird Atlas Project

Lee

Ottosson

Jackson

et al. 2021

Ostrich

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High human population growth and rapid urbanisation, particularly in Africa, have led to an increased interest in the impacts of this land-use change on bird communities. The African Bird Atlas Project, where species presence lists are collected in pentads, is a valuable source of data with which to explore the extent of these impacts. Here, for the first-time, we test for differences in species richness patterns across 50 matched pentad pairs from sub-Saharan Africa classified as either urban (or semi-urban) and rural. We found that species richness was lowest in pentads classified as urban (mean ± SD: 132 ± 59 species), compared with rural (172 ± 54). However, species richness was similar, compared with rural pentads, when levels of urbanisation were maintained at intermediate levels (semi-urban: 141 ± 69). Surprisingly, we found no significant differences in functional diversity measures between any land-use categories. Across most major dietary guilds (carnivores, herbivores, insectivores, granivores) species richness was lower in urbanised pentads and species were often small. However, the overall biomass of these guilds was similar between urbanised and non-urbanised areas, indicating the presence of common urban exploiter species. This resulted in no differences in functional diversity overall. Pollinators and piscivores showed little difference in metrics between rural and urban pentads. According to a model of the functional traits we consider, an African urban exploiter species is best described by being a scavenger, and less likely to be a habitat specialist, but fill a variety of niches. The urban spatial planning implications are that rare and range-restricted species in proximity to cities, as well as large bird species, will require particular attention and conservation measures as African cities continue to expand. Species richness could be maintained with intermediate levels of urban infrastructure development. Les zones urbaniséessont moins riches en espèces mais conservent une diversité fonctionnelle: un aperçu du projet d'Atlas des oiseaux d'Afrique La forte croissance de la population humaine et l'urbanisation rapide, plus particulièrement en Afrique, ont suscité un intérêt accru sur les impacts de ce changement d'utilisation des terres sur les communautés aviaires. Le projet d'Atlas des oiseaux d'Afrique, qui collecte les données relatives à la présence des espèces au travers de pentades (groupe de cinq unités), est un source précieuse de données permettant d'explorer l'étendue de ces impacts. Au travers de cet article, et pour la première fois, nous testons les différences en termes de richesse d'espèces, au travers de modèles basés sur 50 paires de pentades appariées d'Afrique sub-saharienne et classées comme urbaines (ou semi-urbains) ou rurales. Nous avons estimé que la richesse en espèces était la plus faible dans des pentades de catégorie urbaine (moyenne ± σ: 132 ± 59 espèces) par comparaison aux groupes ruraux (172 ± 54 espèces). Néanmoins, il a été constaté que la richesse en espèce...

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Section: Functional Diversity and Dietary Guildssupporting

confidence: 62%

Section: Species Richness and Diversitymentioning

confidence: 91%

Section: What Makes An African Urban Bird?mentioning

confidence: 99%

mentioning

confidence: 99%

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Urban areas have lower species richness, but maintain functional diversity: insights from the African Bird Atlas Project

Lee

Ottosson

Jackson

et al. 2021

Ostrich

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“…Human presence, impervious surfaces and high levels of pollution within urban residential-to-industrial settings continue to shape the world's habitats and modify animal communities (Chamberlain et al 2009;Garaffa et al 2009;Møller 2009;Chamberlain et al 2018;Isaksson 2018;Liker 2020). For example, urban development, associated with increased built-up/impervious surfaces and anthropogenic food sources, causes biotic homogenisation, i.e.…”

mentioning

confidence: 99%

Anthropogenic food availability and body mass maintenance in urban Red-winged Starlings Onychognathus morio

Risi

Sumasgutner

Cunningham

2021

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Anthropogenic food availability is influenced by short-term fluctuations in human presence, especially in core urban areas. Few studies have explored responses to such day-to-week fluctuations, specifically on body mass and body condition of urban birds. Here, we investigated non-breeding body mass maintenance and body condition in Red-winged Starlings Onychognathus morio resident at the University of Cape Town, Western Cape, South Africa, in relation to the proportion of impervious surfaces within their home ranges ('built-up index'). We hypothesised that the built-up index correlates with the starlings' ability to maintain mass, which is mediated by anthropogenic food availability. In a community science project focused on the university campus, we estimated home range sizes and combined these data with systematic behavioural observations (focals), transects to estimate anthropogenic food availability and repeated body mass measurements. Individual starlings with more built-up home ranges were heavier; they were also heavier and in better body condition on high human presence days (weekdays in term time). We found no relationship between the amount of anthropogenic food available or the proportion of anthropogenic food consumed and built-up index, nor between the times spent foraging or foraging efficiency and built-up index. However, anthropogenic food availability was higher on high human presence days when starlings also consumed more anthropogenic food and tended to spend less time foraging, compared with low human presence days (weekends and vacation). There is growing concern that anthropogenic food could have negative consequences during the breeding season, when parents might be provisioning 'junk food' to their offspring. This study provides additional understanding of urban impacts on avian species and the role of anthropogenic food. Disponibilité de la nourriture d'origine anthropique et maintien de la masse corporelle chez les Rufipennes morio en milieu urbainLa disponibilité de la nourriture d'origine anthropique est liée à la fluctuation à court terme de la présence humaine, et ce plus particulièrement dans les centres urbains. Peu d'études ont exploré les réponses à de telles fluctuations quotidiennes à hebdomadaires, et plus spécifiquement sur la masse corporelle et la condition physique des oiseaux urbains. Nous avons étudié le maintien de la masse corporelle et la condition physique des rufipennes morio (Onycognathus morio) résidant à l'université du Cap, dans la province du Cap occidental, en Afrique du Sud, en dehors de la période de reproduction, en fonction des surfaces imperméabilisées comprises dans leur domaine vital (index du bâti). Nous avons émis l'hypothèse que l'index du bâti est corrélé avec la capacité des rufipennes à maintenir leur masse, elle-même liée à la disponibilité de la nourriture anthropique. Dans le cadre d'un projet de science communautaire focalisé sur le campus universitaire, nous avons estimé les tailles de domaines vitaux et avons combiné ces données avec des obs...

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Assessing the state of New Zealand's garden birds from national to local scales

MacLeod

Green

Howard

et al. 2022

Ecol Sol and Evidence

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Better biodiversity indicators are needed to address information gaps, describe trends accurately and robustly and be useful for decisionmakers. Citizen science's potential to help address these challenges often goes unrealized, despite promises by organizers to deliver such information. This paper addresses these challenges by demonstrating the powerful utility of citizen science results for improving our knowledge of the state of New Zealand's garden birds, from the national to the local scale. For 14 species and three annual assessments, we: (a) calculate changes in bird counts over the medium to short term (over 10 and 5 years, respectively); (b) use an alert system to identify trends of interest or concern and collate the assessments in an online interactive tool; and (c) apply the results to address management questions. Seven species have declined nationally in gardens in the medium term, but the population trends of six of these have improved in the short term (the declines of three have been reversed). For Otago, as a regional example, a wider range of medium‐term alerts was initially raised, and positive short‐term changes were also more evident. Performance differed across Otago's districts: positive increases were muted in Dunedin City, while Waitaki had the highest number of increasing species and Central Otago more species rapidly increasing. For 54 neighbourhoods managed by Predator Free Dunedin, as a local example, the baseline medium‐term assessment detected rapid declines in two species, moderate to shallow declines in five species and increases in three species. Based on these findings, managers could improve benefits for biodiversity by using: (a) trends, to direct and evaluate policy investments; (b) benchmarks, to provide social incentives; and (c) targets, to give management purpose and direction. Our case study highlights how citizen science can address biodiversity information gaps and make powerful management contributions at scale by delivering metrics that are robust and comparable across time and space, showing decisionmakers how to readily access and interpret information of interest, building trust and value and highlighting how spatially hierarchical assessments can facilitate multiple end‐user benefits.

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Urban bird trends in a rapidly growing tropical city

Cited by 16 publications

References 36 publications

Urban areas have lower species richness, but maintain functional diversity: insights from the African Bird Atlas Project

Urban areas have lower species richness, but maintain functional diversity: insights from the African Bird Atlas Project

Anthropogenic food availability and body mass maintenance in urban Red-winged Starlings Onychognathus morio

Assessing the state of New Zealand's garden birds from national to local scales

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