Widespread gene flow following range expansion in Anna's Hummingbird.

Anthropogenic changes have altered the historical distributions of many North American taxa. As environments shift, ecological and evolutionary processes can combine in complex ways to either stimulate or inhibit range expansion. Here, we examined the role of evolution in a rapid range expansion whose ecological context has been well-documented, Anna's Hummingbird (Calypte anna).

Quantifying phenology and migratory behaviours of hummingbirds using single-site dynamics and mark-detection analyses.

Nuanced understanding of seasonal movements of partially migratory birds is paramount to species and habitat conservation. Using nascent statistical methods, we identified migratory strategies of birds outfitted with radio-frequency identification (RFID) tags detected at RFID feeders in two sites in California, USA. We quantified proportions of migrants and residents and the seasonal phenology for each movement strategy in Allen's and Anna's hummingbirds; we also validated our methodology by fitting our model to obligate migratory black-chinned hummingbirds.

Retrospective study on admission trends of Californian hummingbirds found in urban habitats (1991-2016).

Background: Hummingbirds are frequently presented to California wildlife rehabilitation centers for medical care, accounting for approximately 5% of overall admissions. Age, sex, and reason for admission could impact hummingbird survivability, therefore identification of these factors could help maximize rehabilitation efforts.

Methods: Mixed-effects logistic regression models were used to identify specific threats to the survival of 6908 hummingbirds (1645 nestlings and 5263 non-nestlings) consisting of five species (), found in urban settings, and admitted to California wildlife rehabilitation centers over 26 years.

Concentrations of Retinol and α-Tocopherol in Tissue Samples From Anna's Hummingbirds ().

Retinol (vitamin A) and α-tocopherol (vitamin E) concentrations were measured in tissue samples (liver, heart, pectoral muscle, and brain) from Anna's Hummingbirds (). Hummingbirds were after-hatch year birds that were sourced from various rehabilitation centers throughout California. Tissues samples were analyzed using high-performance liquid chromatography (HPLC).

TaqMan quantitative real-time PCR for detecting Avipoxvirus DNA in various sample types from hummingbirds.

Background: Avian pox is a viral disease documented in a wide range of bird species. Disease-related detrimental effects can cause dyspnea and dysphagia, and birds with high metabolic requirements, such as hummingbirds, are thus especially vulnerable to the pathogen. Hummingbirds have a strong presence in California, especially in urban environments.

Correction: Use of RFID technology to characterize feeder visitations and contact network of hummingbirds in urban habitats.

[This corrects the article DOI: 10.1371/journal.pone.

Use of RFID technology to characterize feeder visitations and contact network of hummingbirds in urban habitats.

Despite the popular use of hummingbird feeders, there are limited studies evaluating the effects of congregation, sharing food resources and increased contact when hummingbirds visit feeders in urban landscapes. To evaluate behavioral interactions occurring at feeders, we tagged 230 individuals of two species, Anna's and Allen's Hummingbirds, with passive integrated transponder tags and recorded their visits with RFID transceivers at feeders. For detecting the presence of tagged birds, we developed an RFID equipped feeding station using a commercially available antenna and RFID transceiver.

Leukocyte Reference Intervals for Free-Ranging Hummingbirds in Northern California, USA.

Hummingbirds are specialized nectarivores and important ecological pollinators that are the focus of conservation efforts as well as scientific investigations of metabolism and flight dynamics. Despite their importance, basic information is lacking about hummingbird blood cells. We aimed to establish reference intervals for total and differential leukocyte counts from healthy free-ranging hummingbirds in northern California.

Clinical findings and normative ocular data for free-living Anna's (Calypte anna) and Black-chinned (Archilochus alexandri) Hummingbirds.

Objective: To estimate the prevalence of ocular disease and obtain normative ocular data for free-living hummingbirds.

Animals Studied: Two hundred and sixty-three free-living, adult Hummingbirds from coastal and inland central California were studied, including Anna's (Calypte anna, n = 186) and Black-chinned (Archilochus alexandri; n = 77) hummingbirds.

Procedures: Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all individuals.