A Population Bottleneck Did Not Affect Polymorphism Rates in California Swainson's Hawks

Briggs, Christopher W.; Wommack, Elizabeth A.; Sawtelle, Sarah E.; Reynolds, Chevonne; Amar, Arjun

doi:10.3356/jrr-22-52

Cited by 3 publications

(1 citation statement)

References 35 publications

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“…The role of open-source intelligence and citizen science data has expanded in ornithology and continues to increase in popularity due to the relative ease of accessing data, large sample sizes and increasing quality of available metadata. Continued availability of open-source intelligence and citizen science data provides a wealth of information on predator diets [ 27 – 29 , 70 , 76 ], interspecific interactions [ 30 ], polymorphism [ 77 , 78 ], conservation policy and planning [ 79 ], species range shifts [ 80 ], and has the potential to benefit ongoing and future raptor research across large spatial-, demographic- and temporal-scales.…”

Section: Discussionmentioning

confidence: 99%

Continental scale dietary patterns in a New World raptor using web-sourced photographs

Panter,

Naude,

Barbar

et al. 2024

PLoS ONE

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Dietary studies are essential to better understand raptor ecology and resource requirements through time and space, informing species habitat use, interspecific interactions and demographic rates. Methods used to collect data on raptor diets can constrain how dietary analyses can be interpreted. Traditional approaches to study raptor diets, such as analysis of pellets or prey remains, often provide dietary data at the local population level and tend to be restricted to pairs during the breeding season. The increasing use of citizen science data has the potential to provide dietary inferences at larger spatial, demographic and temporal scales. Using web-sourced photography, we explore continental-scale demographic and latitudinal dietary patterns between adult and non-adult Crested Caracaras (Caracara plancus), throughout the species’ range across the Americas. We analysed 1,555 photographs of caracaras feeding and found no age effects on the probabilities of different food groups being included in photographs. The probability of reptiles being included in photographs of caracaras from the northern population was significantly higher than those from the southern population, with the opposite pattern for birds. There were significant latitudinal effects with the probabilities of fishes and invertebrates in the diet of northern caracaras increasing towards the equator. Contrastingly, the probability of mammals in the diet increased away from the equator for both populations. Assuming the focal species is well-sampled, web-sourced photography can improve our understanding of raptor diets at large-scales and complements more traditional approaches. This approach is more accessible to raptor researchers without access to the field or expertise in physical prey identification techniques.

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Section: Discussionmentioning

confidence: 99%

Continental scale dietary patterns in a New World raptor using web-sourced photographs

Panter,

Naude,

Barbar

et al. 2024

PLoS ONE

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Plumage polymorphism in raptors

Robinson,

Lovette,

Walsh

2024

Ornithology

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Trait polymorphisms are a perennially popular topic of study in ecology and evolutionary biology. Plumage polymorphisms occur broadly in birds, with a particularly high rate among the raptors. The regularity of this heritable, melanin-based trait in raptors has prompted research into its potential connections to aspects of life history such as immune response, foraging ecology, and mating systems. Because raptors are a non-monophyletic grouping of multiple orders, they can further be leveraged to explore the eco-evolutionary drivers of recurrent plumage polymorphism phenotypes. Here we characterize plumage polymorphism throughout the raptors and review the existing literature on factors involved in its development and maintenance. We identify patterns and trends in this past body of research and discuss the opportunity to strengthen our understanding of plumage polymorphism through a holistic research approach. Specifically, we detail the likely benefits of applying genomic tools to plumage polymorphism research in raptors while encouraging both a focus on unstudied polymorphic species and on the potential interactions among multiple hypotheses that might promote plumage polymorphism.

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Sexual Dimorphism in Plumage Coloration of Swainson's Hawks (Buteo swainsoni)

Brodman,

Wommack,

Meisman

et al. 2024

Journal of Raptor Research

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Plumage pigmentation and ornamentation can indicate male phenotypic quality in many avian species and represent traits that are often selected for by females. Melanins are some of the most widespread classes of pigments in the animal kingdom and form the many shades of black and brown feather colors across raptor taxa. Eumelanin is responsible for the darker shades of black and brown, whereas pheomelanin is responsible for the lighter brown shades and rusty red coloration that are found in many buteonine raptors, including Swainson’s Hawks (Buteo swainsoni). Plumage polymorphism has been examined in various raptor species along with morphometric differences as a basis for sexual dimorphism; however, the potential for sexual dimorphism in the form of pheomelanin-pigmented plumage has rarely been discussed. We examined this phenomenon in Swainson’s Hawks by digitally sampling breast feathers from adult museum specimens, and we utilized an imaging toolbox for multispectral image analysis in the open-source ImageJ software to compare red pixel values between sexes. We found a significant difference in normalized red pixel value means between male and female birds, with higher redness values strongly correlating with male individuals, regardless of morph type. This indicates a relationship between pheomelanin pigmentation and sex, illustrating a basis for sexual dimorphism within the species, as well as the potential for sexual selection of redder males.

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A Population Bottleneck Did Not Affect Polymorphism Rates in California Swainson's Hawks

Cited by 3 publications

References 35 publications

Continental scale dietary patterns in a New World raptor using web-sourced photographs

Continental scale dietary patterns in a New World raptor using web-sourced photographs

Plumage polymorphism in raptors

Sexual Dimorphism in Plumage Coloration of Swainson's Hawks (Buteo swainsoni)

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