Cardinalis Cardinalis Research Articles

Differences in personality traits and behavioral syndromes in urban and rural Northern Cardinals (Cardinalis cardinalis)

Differences in personality traits and behavioral syndromes in urban and rural Northern Cardinals (Cardinalis cardinalis)

Do vocal mimics learn their mimetic songs from heterospecifics or conspecifics?

Abstract Vocal mimicry can develop either through imitation of heterospecific models (primary mimicry) or through imitation of conspecifics already producing mimetic song (secondary mimicry). Distinguishing primary versus secondary mimicry is important from ecological, evolutionary, and neurobiological perspectives. We outline four empirical strategies for researchers to detect the usage of secondary mimicry: (1) model selection strategy (heterospecific model commonly mimicked but rare or absent locally), (2) usage frequency strategy (syllable types commonly mimicked but rarely used by the model), (3) acoustic structure strategy (acoustic divergence in how a syllable type gets produced by mimics versus models), and (4) syntax strategy (consistent variation between mimic and model in the ordering of syllable types). We then use these strategies to produce evidence for secondary mimicry in northern mockingbirds (Mimus polyglottos), focusing mostly on the mimicked songs of northern cardinals (Cardinalis cardinalis) and tufted titmice (Baeolophus bicolor). As further evidence of the mechanisms by which secondary mimicry might occur, we also demonstrate that mockingbirds match countersing much more frequently in response to conspecifics versus heterospecifics. Deeper questions about the precise extent of primary versus secondary mimicry in mockingbirds and other mimicking species still need answers.

Songbird annual productivity declines with increasing soil lead contamination around nests

Abstract Songbirds incidentally ingest soil contaminated with lead and several species in the Southeast Missouri Lead Mining District have a negative relationship between soil lead concentration and reproduction. We used an individual-based model (IBM) to simulate nesting processes throughout the breeding season to estimate annual productivity for 5 songbirds in relation to soil-lead concentration. We modeled daily nest survival and number fledged in relation to soil lead and incorporated these relationships into the IBM using a Bayesian approach that fully captured parameter uncertainty and process variation. The proportion of the posterior distribution for the effect of soil lead on daily nest survival was mostly negative for Pipilo erythrophthalmus (Eastern Towhee), Passerina cyanea (Indigo Bunting), Cardinalis cardinalis (Northern Cardinal), Sialia sialis (Eastern Bluebird; f = 0.972, 0.990, 0.741, 0.581, respectively), and slightly positive for Spizella pusilla (Field Sparrow; f = 0.680). The proportion of the posterior distribution for the effect of soil lead on the number fledged from successful nests was mostly negative for S. pusilla, P. erythrophthalmus, and C. cardinalis (f = 0.867, 0.585, 0.508, respectively) and positive for P. cyanea and S. sialis (f = 0.773, 0.744). Simulated annual productivity decreased by 0.04–1.47 young/female/year among species across the range of soil lead concentrations, with the greatest declines for P. erythrophthalmus and P. cyanea. The probability of fledging one or more young changed from 51% to 15% for P. erythrophthalmus, 57% to 23% for P. cyanea, 60% to 48% for C. cardinalis, 94% to 84% for S. sialis, and 57% to 64% for S. pusilla as soil-lead concentration around a nest increased from 20 to 4,000 ppm. Most nest failures were the result of predation; therefore, we suggest lead may have affected birds’ behavior at the nest, or affected nest site quality, which resulted in higher nest predation.

Observations of Coordinated Song, Courtship Display, Courtship Feeding, and Copulation in Northern Cardinals (Cardinalis cardinalis) in Virginia

Observations of Coordinated Song, Courtship Display, Courtship Feeding, and Copulation in Northern Cardinals (Cardinalis cardinalis) in Virginia

Analysis of the illegal trade of the Northern Cardinal (Cardinalis cardinalis) in Pomuch, Campeche

El cardenal rojo (Cardinalis cardinalis) está bajo presión por la captura ilegal para venta como ave canora y de ornato. Para conocer la situación actual del comercio de esta especie en la comunidad de Pomuch, Campeche, encuestamos a 9 capturadores, siguiendo el método de "bola de nieve". Encontramos que, anualmente, capturan un promedio de 17 cardenales por capturador, aunque en conjunto pueden atrapar hasta 134 aves anualmente. La bocatrampa con cardenal señuelo es la única técnica utilizada para la captura y los capturadores reportaron una baja mortalidad de 1% a 3% de los cardenales capturados. Los cardenales machos juveniles se venden a mayor precio, llegando a tener un costo de $550 pesos mexicanos para ventas foráneas. La extracción de esta especie, sin regulación alguna, puede generar una disminución de su población. Por consiguiente, recomendamos establecer estrategias para su protección, iniciando con la sensibilización comunitaria mediante la educación ambiental.

Phenotypic signatures of urbanization? Resident, but not migratory, songbird eye size varies with urban-associated light pollution levels.

Urbanization now exposes large portions of the earth to sources of anthropogenic disturbance, driving rapid environmental change and producing novel environments. Changes in selective pressures as a result of urbanization are often associated with phenotypic divergence; however, the generality of phenotypic change remains unclear. In this study, we examined whether morphological phenotypes in two residential species (Carolina Wren [Thryothorus ludovicianus] and Northern Cardinal [Cardinalis cardinalis]) and two migratory species (Painted Bunting [Passerina ciris], and White-eyed Vireo [Vireo griseus]), differed between urban core and edge habitats in San Antonio, Texas, USA. More specifically, we examined whether urbanization, associated sensory pollution (light and noise) and brightness (open, bright areas cause by anthropogenic land use) influenced measures of avian body (mass and frame size) and lateral eye size. We found no differences in body size between urban core and edge habitats for all species except the Painted Bunting, in which core-urban individuals were smaller. Rather than a direct effect of urbanization, this was due to differences in age structure between habitats, with urban-core areas consisting of higher proportions of younger buntings which are, on average, smaller than older birds. Residential birds inhabiting urban-core areas had smaller eyes compared to their urban-edge counterparts, resulting from a negative association between eye size and light pollution and brightness across study sites; notably, we found no such association in the two migratory species. Our findings demonstrate how urbanization may indirectly influence phenotypes by altering population demographics and highlight the importance of accounting for age when assessing factors driving phenotypic change. We also provide some of the first evidence that birds may adapt to urban environments through changes in their eye morphology, demonstrating the need for future research into relationships among eye size, ambient light microenvironment use, and disassembly of avian communities as a result of urbanization.

Utilization of a zoo for mosquito (Diptera: Culicidae) diversity analysis, arboviral surveillance, and blood feeding patterns.

Zoos provide a unique opportunity to study mosquito feeding ecology as they represent areas where exotic animals, free-roaming native animals, humans, and mosquito habitats overlap. Therefore, these locations are a concern for arbovirus transmission to both valuable zoo animals and human visitors. We sampled mosquitoes in and around The Nashville Zoo at Grassmere in Tennessee, USA, over 4 months in 2020 using 4 mosquito trap methods and 12 sampling locations. Mosquitoes were identified to species, Culex mosquitoes were analyzed for arboviruses, and all engorged mosquitoes were preserved for host usage analysis. We captured over 9,000 mosquitoes representing 27 different species, including a new species record for Davidson County, TN (Culex nigripalpus Theobald). Minimum infection rates for West Nile virus (WNV) (Flaviviridae: Flavivirus), St. Louis encephalitis virus (Flaviviridae: Flavivirus), and Flanders virus (Hapavirus: Rhabdoviridae) were 0.79, 0, and 4.17, respectively. The collection of 100 engorged mosquitoes was dominated by Culex pipiens pipiens Linnaeus (38%), Culex erraticus Dyar and Knab (23%), and Culex pipiens pipiens-Culex pipiens quinquefasciatus hybrids (10%). Host DNA from 84 engorged mosquitoes was successfully matched to a variety of host species (n = 23), with just 8 species belonging to the zoo. Wild birds were the most frequently fed upon host, in particular northern cardinals (Cardinalis cardinalis L. Passeriformes: Cardinalidae), which are competent WNV reservoirs. Taken together, our results demonstrate the utility of zoos as sentinels for emerging pathogens, for studying wildlife and human risk of zoonotic diseases, and for assessing vector diversity.

Local weather affects body condition of three North American songbird species on the Texas Coast.

Body condition is a frequently used physiological indicator of avian health and can be affected by an array of environmental variables. Although a number of studies have investigated the specific effects of individual weather variables on body condition in birds, few have analyzed the effects of both temperature and precipitation within the context of an extreme weather event such as hurricanes. In this study, we examined the relationship between breeding-season body condition and daily maximum temperature, daily minimum temperature, and monthly total precipitation for three passerine bird species at the Welder Wildlife Refuge near Rockport, Texas. We also evaluated yearly changes in body condition over a 12-year period for northern cardinals (Cardinalis cardinalis), painted buntings (Passerina ciris), and white-eyed vireos (Vireo griseus), focusing on the extreme precipitation event of Hurricane Harvey, which caused heavy localized flooding. We found that body condition declined with average daily minimum and maximum temperatures, while precipitation had varied, species-specific effects in the three species analyzed. Our results also suggest that northern cardinals experienced a notable reduction in average body condition in the 2 years following Hurricane Harvey. Taken together, we conclude that short-term precipitation and temperature drivers can be important correlates of body condition in songbirds and that severe weather events may reduce body condition in some bird species.

Multiple intrinsic and extrinsic drivers influence the quantity and quality components of seed dispersal effectiveness in the rare shrub Lindera subcoriacea.

Information about seed dispersal effectiveness (SDE) for plant species of conservation concern is rarely available to inform management strategies and actions. For Lindera subcoriacea (bog spicebush, Lauraceae), a rare endemic dioecious shrub of the southeastern United States, we examined the influence of two intrinsic and five extrinsic drivers on the number and proportion of seeds either dispersed, or predated pre- and post-dispersal. The number of seeds dispersed characterizes the quantitative component of SDE, while pre- and post-dispersal seed predation can affect the qualitative component of SDE. Using fruit counts, seed traps, and seed removal depots over multiple years, we estimated that approximately 28% of L. subcoriacea seeds are lost to pre-dispersal predation, 69% of seeds are dispersed, 3% of seeds fail to disperse, and 65% of dispersed seeds are predated post-dispersal. We observed substantial variation in these three processes among individuals. We also found that both intrinsic (plant height, crop size) and extrinsic (understory cover, time since last fire, conspecific fruiting neighborhood, substrate) drivers differentially influenced the three processes. We identified four generalist, seasonally frugivorous, avian visitors at fruiting individuals that likely act as variably effective dispersers, while the Northern Cardinal (Cardinalis cardinalis L.) is a seed predator. Rodent granivores were important pre- and post-dispersal seed predators. The magnitude of our pre-dispersal and post-dispersal seed predation estimates suggest that, given the low fecundity of L. subcoriacea, conservation strategies should emphasize facilitating dispersal and reducing the effects of seed predation.

Multi-Year Comparison of Community- and Species-Level West Nile Virus Antibody Prevalence in Birds from Atlanta, Georgia and Chicago, Illinois, 2005-2016.

West Nile virus (WNV) is prevalent in the United States but shows considerable variation in transmission intensity. The purpose of this study was to compare patterns of WNV seroprevalence in avian communities sampled in Atlanta, Georgia and Chicago, Illinois during a 12-year period (Atlanta 2010-2016; Chicago 2005-2012) to reveal regional patterns of zoonotic activity of WNV. WNV antibodies were measured in wild bird sera using ELISA and serum neutralization methods, and seroprevalence among species, year, and location of sampling within each city were compared using binomial-distributed generalized linear mixed-effects models. Seroprevalence was highest in year-round and summer-resident species compared with migrants regardless of region; species explained more variance in seroprevalence within each city. Northern cardinals were the species most likely to test positive for WNV in each city, whereas all other species, on average, tested positive for WNV in proportion to their sample size. Despite similar patterns of seroprevalence among species, overall seroprevalence was higher in Atlanta (13.7%) than in Chicago (5%). Location and year of sampling had minor effects, with location explaining more variation in Atlanta and year explaining more variation in Chicago. Our findings highlight the nature and magnitude of regional differences in WNV urban ecology.

Multiple carotenoid-based signals are enhanced despite poor body condition in urban male and female Northern Cardinals (Cardinalis cardinalis)

Si los humanos pretenden coexistir con la vida silvestre, debemos entender cómo nuestras actividades impactan los sistemas de comunicación de poblaciones animales urbanas. Ya sabemos bastante acerca de los efectos del ruido antropogénico en el canto de las aves pero se conoce relativamente poco acerca de cómo las señales visuales aviares son afectadas por la urbanización. Este efecto podría ocurrir si la urbanización altera la alimentación de la que dispone la especie cuyo color se basa en los carotenoides, que deben obtener de su dieta. Durante 3 años comparamos un conjunto completo de señales visuales en machos y hembras de cardenal norteño (Cardinalis cardinalis) de poblaciones rurales y urbanas. Nuestra predicción fue que las aves urbanas iban a mostrar señales más fuertes basadas en carotenoides, ya que tienen acceso a mayor cantidad de carotenoides provenientes de plantas invasoras que proliferan en las ciudades. Usamos espectrometría de reflectancia, análisis de imagen digital y modelos visuales aviares para cuantificar el tono, la saturación y el brillo de las señales del pecho (machos), la parte inferior del ala (hembras) y el pico (machos y hembras). Comparados con los machos de zonas rurales, los machos de zonas urbanas tenían más rojas las plumas del pecho en un año y el pico más rojo en cada año. Las hembras de zonas urbanas tenían mayor saturación de color en la parte inferior del ala que las hembras de zonas rurales cada año. Estas diferencias de color eran suficientes como para ser distinguidas por el sistema visual de las aves. El color de pico de las hembras no varió entre sitios. De manera interesante, las aves urbanas tienen significativamente menos condición corporal relacionada con la masa que las aves rurales. Así, tanto machos como hembras de zonas urbanas pueden desplegar señales basadas en carotenoides a pesar de estar en relativamente peor condición que las aves rurales. Sugerimos que las aves urbanas tienen mayor acceso a los carotenoides a través de la madreselva invasora (Lonicera spp), que las aves rurales. Este incremento de color podría afectar el contenido de la información de las señales y las dinámicas de los sistemas sociales y reproductivos. Estos resultados contrastan con la tendencia general de que las aves urbanas tienen menos color que las rurales y resaltan los potenciales efectos complejos y variados de la urbanización en la comunicación animal. Palabras clave: color de pico, color de plumaje, espectrometría de reflectancia, modelo visual aviar, urbanización.

Host selection and forage ratio in West Nile virus-transmitting Culex mosquitoes: Challenges and knowledge gaps.

BackgroundTo date, no specific therapy or vaccination is available for West Nile virus (WNV) infections in humans; preventive strategies represent the only possibility to control transmission. To focus these strategies, detailed knowledge of the virus dynamics is of paramount importance. However, several aspects of WNV transmission are still unclear, especially regarding the role of potential vertebrate host species.Whereas mosquitoes’ intrinsic characteristics cause them to favour certain hosts (host preference), absolute selection is impossible in natural settings. Conversely, the selection carried out among available hosts and influenced from hosts’ availability and other ecological/environmental factors is defined as host selection.Methodology/Principal findingsIn July 2022, we searched PubMed database for original articles exploring host selection among WNV-transmitting Culex mosquitoes, the main WNV vector. We considered only original field studies estimating and reporting forage ratio. This index results from the ratio between the proportion of blood meals taken by mosquitoes on potential host species and the hosts’ relative abundance.From the originally retrieved 585 articles, 9 matched the inclusion criteria and were included in this review. All but one of the included studies were conducted in the Americas, six in the United States, and one each in Mexico and Colombia. The remaining study was conducted in Italy.American Robin, Northern Cardinal, and House Finch were the most significantly preferred birds in the Americas, Common Blackbird in Italy.Conclusions/SignificanceAlthough ornithophilic, all observed WNV-transmitting mosquitoes presented opportunistic feeding behaviour. All the observed species showed potential to act as bridges for zoonotic diseases, feeding also on humans. All the observed mosquitoes presented host selection patterns and did not feed on hosts as expected by chance alone.The articles observe different species of mosquitoes in different environments. In addition, the way the relative host abundance was determined differed. Finally, this review is not systematic. Therefore, the translation of our results to different settings should be conducted cautiously.

Thrips (Insecta: Thysanoptera) Associated with Two Species of Live Birds (Cardinalis cardinalis and Zenaida macroua) in Northeast Arkansas

Dispersal is an important factor in shaping ecosystems and patterns of biodiversity. However, animals use several different modes of dispersal, each of which can have varying impacts on the ecology and evolutionary history of a group. One of these modes is phoresy, when an animal (the phorant) will temporarily attach itself to another animal (the host) as a means of dispersal. This behavior has been described in many groups of animals, but very infrequently in the thrips (Insecta: Thysanoptera). Here, we report the collection of 2 species of live thrips, Hoplothrips sp. and Neohydatothrips variabilis, from 2 species of live birds, Cardinalis cardinalis (Northern Cardinal) and Zenaida macroura (Mourning Dove), respectively, in northeast Arkansas. Most previous records of thrips associated with birds were from nesting material or found on deceased birds. The presence of thrips on live birds suggests some thrips are phoretic on birds, or at the very least that interactions between thrips and birds are more frequent than previously assumed.

Northern Cardinal Nesting in Wyoming

Northern Cardinal Nesting in Wyoming

Geographic variation in morphology of Northern Cardinals: possible application of Bergmann’s Rule?

DeVries, M., M. Waraczynski, D. T. Baldassarre, M. C. Slevin, R. Anderson, and J. M. Jawor. 2022. Geographic variation in morphology of Northern Cardinals: possible application of Bergmann’s Rule? Journal of Field Ornithology 93(2):9. https://doi.org/10.5751/JFO-00121-930209

Species-Specific Responses of Bird Song Output in the Presence of Drones

Drones are now widely used to study wildlife, but their application in the study of bioacoustics is limited. Drones can be used to collect data on bird vocalizations, but an ongoing concern is that noise from drones could change bird vocalization behavior. To test for behavioral impact, we conducted an experiment using 30 sound localization arrays to track the song output of 7 songbird species before, during, and after a 3 min flight of a small quadcopter drone hovering 48 m above ground level. We analyzed 8303 song bouts, of which 2285, from 184 individual birds were within 50 m of the array centers. We used linear mixed effect models to assess whether patterns in bird song output could be attributed to the drone’s presence. We found no evidence of any effect of the drone on five species: American Robin Turdus migratorius, Common Yellowthroat Geothlypis trichas, Field Sparrow Spizella pusilla, Song Sparrow Melospiza melodia, and Indigo Bunting Passerina cyanea. However, we found a substantial decrease in Yellow Warbler Setophaga petechia song detections during the 3 min drone hover; there was an 81% drop in detections in the third minute (Wald test, p < 0.001) compared with before the drone’s introduction. By contrast, the number of singing Northern Cardinal Cardinalis cardinalis increased when the drone was overhead and remained almost five-fold higher for 4 min after the drone departed (p < 0.001). Further, we found an increase in cardinal contact/alarm calls when the drone was overhead, with the elevated calling rate lasting for 2 min after the drone departed (p < 0.001). Our study suggests that the responses of songbirds to drones may be species-specific, an important consideration when proposing the use of drones in avian studies. We note that recent advances in drone technology have resulted in much quieter drones, which makes us hopeful that the impact that we detected could be greatly reduced.

Effects of patch-burn grazing and rotational grazing on grassland bird abundance, species richness, and diversity in native grassland pastures of the Midsouth USA

Declines in native warm season grasslands have been linked to grassland bird population decline due to habitat loss including conversion to non-native grasses. Rotational grazing (ROT) and patch-burn grazing (PBG) are two possible tools to restore native warm-season grasses (NWSG) on working-lands in the Mid-South USA and thus aid in the recovery of grassland bird populations. This project compares ROT, PBG, and before treatment implementation to assess their effects on grassland-associated bird species. At three research sites between KY and TN, 14–10 ha NWSG pastures were established and randomly assigned 7 pastures each to ROT and PBG treatment and monitored avian relative abundance during the breeding season from 2014 to 2017. Avian call count data and vegetation characteristics were collected in 2014 and treated as a before treatment year. Following 2014, ROT and PBG treatments were implemented across each respective research site. We used the open N-mixture model framework to estimate avian relative abundance related to year, treatments, research site, and landscape and within-field variables. Avian species richness and diversity were calculated for each treatment, research site, and year. Landscape variables, within-field variables, and research sites exerted more influence on relative abundance than ROT or PBG. Grassland-associated bird species relative abundance and species richness/diversity were affected by habitat disturbances (both ROT and PBG) but varied by species and site. Field sparrows [Spizella pusilla] had the highest increase in relative abundance (9.68 ± 1.24 birds/point count location or 1.77 ha) while northern cardinals [Cardinalis cardinalis] exhibited a significant decrease in relative abundance (3.44 ± 1.54 birds/point count location) following treatment implementation on specific research sites. Species diversity and richness did not differ between ROT and PBG treatments. However, a site and year difference were observed for both estimates. Using ROT and/or PBG to create habitat disturbances can alter within-field variables (i.e., vegetation height) which, taken into context with landscape variables, could impact grassland bird populations and diversity depending on grassland bird species habitat requirements. Our research provided the baseline information for ROT and PBG impacts on grassland birds in the east/southeastern USA. However, we believe future research should focus on breeding and annual fecundity to better understand how populations will change over time and how working lands conservation might aid this conservation effort without a reduction in livestock productivity.

Tick infestation of birds across a gradient of urbanization intensity in the United States Great Plains

Migratory birds play an important role in large-scale movements of ticks and tick-borne pathogens, yet little is known about tick infestation of resident birds (e.g., non-migratory species and migratory species during the breeding season), especially in urban ecosystems. We captured birds during the breeding season in parks and greenspaces in Oklahoma City, Oklahoma, USA, to evaluate overall tick infestation patterns and to determine if urbanization influences infestation prevalence (the proportion of birds parasitized) and intensity (the number of ticks on infested birds). Of 459 birds, 111 (24.2%) had ≥ 1 tick, a high proportion of infestation compared with past North American studies. The most frequently infested species were Carolina Wren (Thryothorus ludovicianus; 56%), Brown Thrasher (Toxostoma rufum; 37%), and Northern Cardinal (Cardinalis cardinalis; 27%). The Lone Star Tick (Amblyomma americanum) comprised half (51%; n = 322) of all ticks on birds; other species sampled included Gulf Coast Tick (A. maculatum) (36%) and Rabbit Tick (Haemaphysalis leporispalustris) (13%). Urbanization intensity (i.e., the percentage of developed land around sites) was inversely related to infestation prevalence for all birds combined and for Carolina Wren, but intensity of infestation was unrelated to urbanization. Our results suggest that non-migratory and migratory birds during sedentary periods are important carriers of ticks in urban areas, and that tick infestation patterns can be influenced by the level of urbanization in the surrounding landscape. Clarifying how urban birds influence tick populations, and how urbanization shapes bird-tick interactions, will increase understanding of tick-borne disease ecology in urban ecosystems.

Culex quinquefasciatus (Diptera: Culicidae) survivorship following the ingestion of bird blood infected with Haemoproteus sp. parasites

Arthropod vectors are frequently exposed to a diverse assemblage of parasites, but the consequence of these infections on their biology and behavior are poorly understood. We experimentally evaluated whether the ingestion of a common protozoan parasite of avian hosts (Haemoproteus spp.; Haemosporida: Haemoproteidae) impacted the survivorship of Culex quinquefasciatus (Say) (Diptera: Culicidae). Blood was collected from wild northern cardinals (Cardinalis cardinalis) in College Station, Texas, and screened for the presence of Haemoproteus spp. parasites using microscopic and molecular methods. Experimental groups of Cx. quinquefasciatus mosquitoes were offered Haemoproteus-positive cardinal blood through an artificial feeding apparatus, while control groups received Haemoproteus-negative cardinal blood or domestic canary (Serinus canaria domestica) blood. Culex quinquefasciatus mosquitoes exposed to Haemoproteus infected cardinal blood survived significantly fewer days than mosquitoes that ingested Haemoproteus-negative cardinal blood. The survival of mosquitoes fed on positive cardinal blood had a median survival time of 18 days post-exposure and the survival of mosquitoes fed on negative cardinal blood exceeded 50% across the 30 day observation period. Additionally, mosquitoes that fed on canary controls survived significantly fewer days than cardinal negative controls, with canary control mosquitoes having a median survival time of 17 days. This study further supports prior observations that Haemoproteus parasites can be pathogenic to bird-biting mosquitoes, and suggests that Haemoproteus parasites may indirectly suppress the transmission of co-circulating vector-borne pathogens by modulating vector survivorship. Our results also suggest that even in the absence of parasite infection, bloodmeals from different bird species can influence mosquito survivorship.

Homeward bound: canopy cover and species identity influence non-breeding season homing success and speed in forest birds

BackgroundEfficient and safe movement is fundamental for wild birds to thrive in their environments. For arboreal forest animals, especially birds, canopy cover has a large impact on birds’ daily movements and is a crucial component of conservation strategies seeking to retain avian population in disturbed or urban habitats.MethodsWe translocated woodland bird species utilizing different forest strata during two non-breeding seasons in Gainesville, FL, USA. We used linear model and generalized linear model to examine the effects of canopy cover and species identity on homing success and speed.ResultsAmong our study species of Tufted Titmouse (Baeolophus bicolor), Carolina Chickadee (Poecile carolinensis), and Northern Cardinal (Cardinalis cardinalis), we found that Carolina Chickadees and Tufted Titmice were more likely to return than Northern Cardinals. Among birds that successfully returned, homing speed is significantly affected by forest canopy cover and species identity (titmice had higher homing speed than cardinals). Birds return much faster in landscape with higher canopy cover.ConclusionsThis study presented evidence of species identity’s effect on homing success and speed in common feeder bird species in Southeast US and provided further evidence that bird movements in the suburban land cover are constrained by low canopy cover.