Endogenous biomarkers reveal diet partitioning among three sympatric species of swallows

The Auk ◽  
2021 ◽  
Author(s):  
Kaelyn H Bumelis ◽  
Michael D Cadman ◽  
Keith A Hobson
Keyword(s):  
Isotope Analysis ◽  
Sympatric Species ◽  
Tree Swallow ◽  
Population Declines ◽  
Interspecific Differences ◽  
Cliff Swallow ◽  
Aerial Insectivores ◽  
Breeding Grounds ◽  
Potential Factors ◽  
Δ 15N

Abstract Since the early 1990s, aerial insectivorous birds have shown serious population declines in North America, but it is not clear if factors common to all species within this guild account for these declines. Among sympatric swallows, population trends differ, and this may be due to differences in ecology operating throughout the annual cycle. Although these species all feed on aerial insects, prey taxa can differ tremendously in their “aeroecology” and use by swallows. We examined the potential for dietary differences among three species of swallows, Barn Swallow (Hirundo rustica), Cliff Swallow (Petrochelidon pyrrhonota), and Tree Swallow (Tachycineta bicolor), breeding sympatrically in southern Ontario, Canada. Potential interspecific differences in nestling diet were examined using two endogenous biomarkers, DNA barcoding of nestling feces and stable isotope analysis (δ 2H, δ 13C, δ 15N) of nestling feathers. We found evidence for differences in dietary sources of provisioned young where Barn Swallows provisioned more terrestrial-based prey, Cliff Swallows provisioned an intermediate diet, and Tree Swallows the most aquatic-emergent insect diet. We suggest this information may help to identify potential factors contributing to differential declines of aerial insectivores operating on the breeding grounds, including diet quality.

scholarly journals Breeding origins and migratory connectivity at a northern roost of Vaux’s Swift, a declining aerial insectivore

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Ellis L Smith ◽  
Matthew W Reudink ◽  
Peter P Marra ◽  
Ann E Mckellar ◽  
Steven L Van Wilgenburg
Keyword(s):  
Stable Isotope ◽  
Annual Cycle ◽  
Isotope Analysis ◽  
Vancouver Island ◽  
Cluster Solution ◽  
Migratory Connectivity ◽  
Breeding Sites ◽  
Aerial Insectivores ◽  
Breeding Grounds ◽  
Weak Connectivity

ABSTRACT Populations of Vaux’s Swift (Chaetura vauxi), like those of many aerial insectivores, are rapidly declining. Determining when and where populations are limited across the annual cycle is important for their conservation. Establishing the linkages between wintering and breeding sites and the strength of the connections between them is a necessary first step. In this study, we analyzed 3 stable isotopes (δ13C, δ15N, δ2H) from feathers collected during spring migration from Vaux’s Swifts that perished during a stopover on Vancouver Island, British Columbia, Canada. We previously analyzed claw tissue (grown during winter) from the same individuals, revealing that the swifts likely wintered in 2 or 3 locations/habitats. Here, we used stable isotope analysis of flight feathers presumed to have been grown on, or near, the breeding grounds to determine the likely previous breeding locations and presumed destinations for the swifts. Stable isotope values (δ13C, δ15N, δ2H) showed no meaningful variation between age classes, sexes, or with body size. Surprisingly, ~26% of the birds sampled had feather isotope values that were not consistent with growth on their breeding grounds. For the remaining birds, assigned breeding origins appeared most consistent with molt origins on Vancouver Island. Overall, migratory connectivity of this population was relatively weak (rM = 0.07). However, the degree of connectivity depended on how many winter clusters were analyzed; the 2-cluster solution suggested no significant connectivity, but the 3-cluster solution suggested weak connectivity. It is still unclear whether low migratory connectivity observed for Vaux’s Swift and other aerial insectivores may make their populations more or less vulnerable to habitat loss; therefore, further efforts should be directed to assessing whether aerial insectivores may be habitat limited throughout the annual cycle.

scholarly journals Birds advancing lay dates with warming springs face greater risk of chick mortality

2020 ◽  
Vol 117 (41) ◽  
pp. 25590-25594 ◽  
Author(s):  
J. Ryan Shipley ◽  
Cornelia W. Twining ◽  
Conor C. Taff ◽  
Maren N. Vitousek ◽  
Andrea Flack ◽  
...  
Keyword(s):  
Climate Change ◽  
Reproductive Success ◽  
Egg Laying ◽  
Tree Swallow ◽  
Population Declines ◽  
Chick Survival ◽  
Ambient Temperatures ◽  
Inclement Weather ◽  
Aerial Insectivores

In response to a warming planet with earlier springs, migratory animals are adjusting the timing of essential life stages. Although these adjustments may be essential for keeping pace with resource phenology, they may prove insufficient, as evidenced by population declines in many species. However, even when species can match the tempo of climate change, other consequences may emerge when exposed to novel conditions earlier in the year. Here, using three long-term datasets on bird reproduction, daily insect availability, and weather, we investigated the complex mechanisms affecting reproductive success in an aerial insectivore, the tree swallow (Tachycineta bicolor). By examining breeding records over nearly half a century, we discovered that tree swallows have continuously advanced their egg laying by ∼3 d per decade. However, earlier-hatching offspring are now exposed to inclement weather events twice as often as they were in the 1970s. Our long-term daily insect biomass dataset shows no long-term trends over 25 y but precipitous drops in flying insect numbers on days with low ambient temperatures. Insect availability has a considerable impact on chick survival: Even a single inclement weather event can reduce offspring survival by >50%. Our results highlight the multifaceted threats that climate change poses on migrating species. The decoupling between cold snap occurrence and generally warming spring temperatures can affect reproductive success and threaten long-term persistence of populations. Understanding the exact mechanisms that endanger aerial insectivores is especially timely because this guild is experiencing the steepest and most widespread declines across North America and Europe.

scholarly journals Omega-3 long-chain polyunsaturated fatty acids support aerial insectivore performance more than food quantity

2016 ◽  
Vol 113 (39) ◽  
pp. 10920-10925 ◽  
Author(s):  
Cornelia W. Twining ◽  
J. Thomas Brenna ◽  
Peter Lawrence ◽  
J. Ryan Shipley ◽  
Troy N. Tollefson ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Tree Swallow ◽  
Omega 3 ◽  
Food Quantity ◽  
Aerial Insectivore ◽  
Aerial Insectivores ◽  
Terrestrial Insects ◽  
Long Chain

Once-abundant aerial insectivores, such as the Tree Swallow (Tachycineta bicolor), have declined steadily in the past several decades, making it imperative to understand all aspects of their ecology. Aerial insectivores forage on a mixture of aquatic and terrestrial insects that differ in fatty acid composition, specifically long-chain omega-3 polyunsaturated fatty acid (LCPUFA) content. Aquatic insects contain high levels of both LCPUFA and their precursor omega-3 PUFA, alpha-linolenic acid (ALA), whereas terrestrial insects contain much lower levels of both. We manipulated both the quantity and quality of food for Tree Swallow chicks in a full factorial design. Diets were either high-LCPUFA or low in LCPUFA but high in ALA, allowing us to separate the effects of direct LCPUFA in diet from the ability of Tree Swallows to convert their precursor, ALA, into LCPUFA. We found that fatty acid composition was more important for Tree Swallow chick performance than food quantity. On high-LCPUFA diets, chicks grew faster, were in better condition, and had greater immunocompetence and lower basal metabolic rates compared with chicks on both low LCPUFA diets. Increasing the quantity of high-LCPUFA diets resulted in improvements to all metrics of performance while increasing the quantity of low-LCPUFA diets only resulted in greater immunocompetence and lower metabolic rates. Chicks preferentially retained LCPUFA in brain and muscle when both food quantity and LCPUFA were limited. Our work suggests that fatty acid composition is an important dimension of aerial insectivore nutritional ecology and reinforces the importance of high-quality aquatic habitat for these declining birds.

scholarly journals Interacting effects of cold snaps, rain, and agriculture on the fledging success of a declining aerial insectivore

2021 ◽  
Author(s):  
Daniel Roy Garrett ◽  
Fanie Pelletier ◽  
Dany Garant ◽  
Marc Bélisle
Keyword(s):  
Climate Change ◽  
Agricultural Intensification ◽  
Prey Availability ◽  
Tree Swallow ◽  
Landscape Changes ◽  
Population Declines ◽  
Negative Effects ◽  
Fledging Success ◽  
Inclement Weather ◽  
Aerial Insectivore

Climate change predicts the increased frequency, duration, and intensity of inclement weather periods, such as unseasonably low temperatures and prolonged precipitation. Many migratory species have advanced the phenology of important life history stages, and as a result are likely exposed to these periods of inclement spring weather more often, thus risking reduced fitness and population growth. For declining avian species, including aerial insectivores, anthropogenic landscape changes such as agricultural intensification are another driver of population declines. These landscape changes may affect the foraging ability of food provisioning parents, as well as reduce the probability a nestling will survive periods of inclement weather, through for example pesticide exposure impairing thermoregulation and punctual anorexia. Breeding in agro-intensive landscapes may thus exacerbate the negative effects of inclement weather under climate change. We used daily temperatures related to significant reductions of insect prey availability (cold snaps), combined with measures of precipitation, and assessed their impact on Tree Swallow (Tachycineta bicolor) fledging success, a declining aerial insectivore breeding across a gradient of agricultural intensification. Fledging success decreased with the number of cold snap days experienced by a brood, and this relationship was worsened during periods of prolonged precipitation. We further found the overall negative effects of experiencing periods of inclement weather are exacerbated in more agro-intensive landscapes. Our results indicate that two of the primary hypothesized drivers of many avian population declines may interact to further increase the rate of declines in certain landscape contexts.

scholarly journals Arthropod Resource Partitioning Among Omnivorous Tanagers (Tangara SPP.) in Western Ecuador

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 197-209 ◽  
Author(s):  
Kazuya Naoki
Keyword(s):  
Resource Use ◽  
Foraging Ecology ◽  
Bird Species ◽  
Sympatric Species ◽  
Factors Affecting ◽  
Use Patterns ◽  
Interspecific Differences ◽  
Fruit Species ◽  
Mixed Species Flocks ◽  
Different Characteristics

Abstract The distribution and abundance of food are primary factors affecting resource-use patterns in birds. Many bird species eat several food types, which may differ in their distribution and overall abundance. I studied foraging ecology of seven sympatric species of Tangara at Mindo, Ecuador, to determine whether the patterns of resource use differed between two food types: arthropods and fruits. Interspecific differences in arthropod-foraging were manifested in the fine segregation of microhabitat preference combined with different habitat use. By contrast, interspecific differences in fruit-foraging were manifested in preferences for different plant genera, often associated with different habitats. No evidence was found for spatial partitioning of the same fruit species. Interspecific overlap in fruit-for- aging was 3× higher than that in arthropod-foraging, and species of Tangara that frequently joined the same mixed-species flocks differed largely in arthropod-foraging but overlapped greatly in fruit-foraging. The differences in patterns between arthropod and fruit-foraging may be explained by the different characteristics of arthropods and fruits as food resources. High sympatry of species of Tangara and other omnivorous tanagers, in general, appears to be maintained not because fruits are abundant, resulting in little competition for them, but because these tanagers specialize on different microhabitats for foraging arthropods. Segregación de Artrópodos como Recurso Alimenticio de Tangaras Omnívoras (Tangara spp.) en el Oeste de Ecuador

scholarly journals Color Differences Among Closely Related Species of Red-Breasted Meadowlarks (Sturnella)

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 605-616
Author(s):  
Pilar Benites ◽  
Pablo L. Tubaro ◽  
Darío A. Lijtmaer ◽  
Stephen C. Lougheed ◽  
Muir D. Eaton
Keyword(s):  
Related Species ◽  
Short Wavelength ◽  
Visual Space ◽  
Color Discrimination ◽  
Threshold Value ◽  
Sympatric Species ◽  
Closely Related Species ◽  
Interspecific Differences ◽  
Sexually Selected Traits ◽  
Color Differences

Abstract Abstract. Interspecific differences in sexually selected traits may be important for maintaining reproductive isolation among closely related species living in sympatry. We present the first study of plumage color differences among males of partially sympatric species of South American red-breasted meadowlarks—the White-browed Blackbird (Sturnella superciliaris), the Pampas Meadowlark (S. defilippii), and the Long-tailed Meadowlark (S. loyca)—using reflectance spectrophotometry and the avian visual model of Vorobyev and Osorio (1998). Reflectance values of sexually dichromatic red plumage patches were measured on study skins. Total reflectance, reflectance in the short wavelength part of the spectrum, and several measures of spectral shape were extracted directly from the spectra. Our analyses revealed that S. loyca and S. defilippii were brighter and had higher reflectance in the short wavelength part of the spectrum than S. superciliaris. Minimum reflectance was located at higher wavelengths in breeding than in nonbreeding plumage. Interspecific distances in avian visual space obtained from the Vorobyev and Osorio (1998) model were considerably higher than the threshold value for color discrimination, indicating that the differences found are also detectable by birds. Taken together, these results show that the red plumage patches of these three species present significant color differences throughout the year, not only in the visible but also in the UV part of the spectrum.

New and little-known species of feather mites (Acari: Analgoidea: Pteronyssidae) from birds in North America

2006 ◽  
Vol 138 (2) ◽  
pp. 165-188 ◽  
Author(s):  
Sergei V. Mironov ◽  
Terry D. Galloway
Keyword(s):  
North America ◽  
Tree Swallow ◽  
Feather Mites ◽  
New Host ◽  
Cliff Swallow ◽  
Northern Flicker ◽  
Picoides Pubescens ◽  
Colaptes Auratus ◽  
First Time ◽  
New Host Records

AbstractIn this paper, we review the pteronyssid feather mites of the genera Pteronyssus Robin, Scutulanyssus Mironov, and Stenopteronyssus Faccini and Atyeo found in the course of an investigation into ectoparasites of birds in Canada. Five new species of feather mites are described: Pteronyssus sphyrapicinussp. nov. from the Yellow-bellied Sapsucker, Sphyrapicus varius (L.); Stenopteronyssus proctoraesp. nov. from the Northern Flicker, Colaptes auratus (L.); Scutulanyssus progneisp. nov. and Scutulanyssus subissp. nov. from the Purple Martin, Progne subis (L.); and Scutulanyssus petrochelidonissp. nov. from the Cliff Swallow, Petrochelidon pyrrhonota (Vieillot). New host records are provided for Pteronyssus picoides Černy and Schumilo from the Downy Woodpecker, Picoides pubescens (L.), and for Scutulanyssus obscurus (Berlese) from the Cliff Swallow; Pteronyssus brevipes Berlese and Scutulanyssus hirundicolus Mironov are formally recorded in North America for the first time; and Pteronyssus centurus McDaniel and Price is reported for the first time in Canada, from Lewis' Woodpecker, Melanerpes lewis (Gray). Scutulanyssus tyrrelli (Canestrini) is reported for the first time in Manitoba from the Tree Swallow, Tachycineta bicolor (Vieillot). Keys are provided for all species of Pteronyssus and Scutulanyssus found in North America.

scholarly journals Population decline and range contraction of the Egyptian Vulture Neophron percnopterus in the Balkan Peninsula

2014 ◽  
Vol 25 (4) ◽  
pp. 440-450 ◽  
Author(s):  
METODIJA VELEVSKI ◽  
STOYAN C. NIKOLOV ◽  
BEN HALLMANN ◽  
VLADIMIR DOBREV ◽  
LAVRENTIS SIDIROPOULOS ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Population Decline ◽  
Balkan Peninsula ◽  
Population Declines ◽  
Egyptian Vulture ◽  
Breeding Grounds ◽  
Conservation Actions ◽  
Causes Of Mortality ◽  
Yugoslav Republic

SummaryThe Egyptian Vulture has been classified as ‘Endangered’ due to a rapid population decline in India and long term declines in Europe and Africa. Although the species has been reported to be declining in Eastern Europe, no quantitative assessment of the magnitude or the causes for population declines are available. We used monitoring data from the Balkan Peninsula to estimate changes in population size and extent of occurrence of Egyptian Vultures between 1980 and 2013. We quantified population trends in three countries (Bulgaria, Greece and the former Yugoslav Republic [FYR] of Macedonia) to assess whether population declines are similar within the Balkan range states. We found a rapid and consistent decline of the Egyptian Vulture population that was largely similar among the three countries (λ = 0.940 in FYR of Macedonia, 0.951 in Bulgaria, 0.920 in Greece). As a consequence of population declines, the breeding range of Egyptian Vultures has contracted and the population in the Balkan Peninsula has fragmented into six subpopulations separated by more than 80 km. Population declines may be driven by factors such as poisoning, electrocution, direct persecution and changes in food availability which operate at large spatial scales and affect birds both on breeding grounds as well as during migration and wintering. Because the relative importance of threats to the survival of Egyptian Vultures are poorly understood, there is a critical need for research into causes of mortality and potential conservation actions that may halt and reverse population declines.

scholarly journals Stable isotope analysis of diet confirms niche separation of two sympatric species of Namib Desert lizard

2016 ◽  
Vol 11 (1) ◽  
pp. 60-75 ◽  
Author(s):  
Ian W. MURRAY ◽  
Hilary M. LEASE ◽  
Robyn S. HETEM ◽  
Duncan MITCHELL ◽  
Andrea FULLER ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Sympatric Species ◽  
Niche Separation ◽  
Namib Desert ◽  
Desert Lizard

Investigation of the geographic origin of burrowing owl fleas with implications for the ecology of plague

The Auk ◽  
2019 ◽  
Vol 136 (1) ◽  
Author(s):  
Kara A Navock ◽  
David H Johnson ◽  
Samantha Evans ◽  
Matthew J Kohn ◽  
James R Belthoff
Keyword(s):  
Isotope Analysis ◽  
Geographic Origin ◽  
Breeding Ground ◽  
Athene Cunicularia ◽  
Wintering Grounds ◽  
Burrowing Owls ◽  
Burrowing Owl ◽  
Isotopic Compositions ◽  
Breeding Grounds ◽  
Host Parasite

ABSTRACT Host-parasite relationships between Western Burrowing Owls (Athene cunicularia hypugaea) and the fleas (Pulex irritans, Siphonaptera:Pulicidae) they harbor were studied to understand the extent to which migratory Burrowing Owls translocated fleas from wintering grounds to breeding grounds. This has implications for host-parasite relationships in Burrowing Owls and also potentially for the dynamics of plague, as Burrowing Owl distributions overlap plague foci, owls inhabit fossorial mammal colonies where epizootic outbreaks of plague occur, and owls may harbor species of flea that are competent plague vectors. We used hydrogen stable isotope analysis to help elucidate geographic origins of fleas collected from adults and nestlings in 2 migratory populations of Burrowing Owls in Idaho and Oregon, USA. For adults, we posited that bird-mediated dispersal would impart flea isotopic compositions representative of southern latitudes and be similar to owl toenail tissue recently grown on wintering grounds, but they would differ from contour feathers presumably grown on breeding grounds the previous year. We assumed nestling feathers and toenails would have isotopic compositions representative of the breeding grounds. We analyzed contour feathers and toenails from adults collected shortly after they arrived in breeding grounds following spring migration and from nestlings later in the breeding season, to which we compared isotopic compositions in fleas collected from individuals of both age classes. Fleas on nestlings in both populations had isotopic compositions that did not differ from nestling feathers and toenails, suggesting that nestling fleas had breeding ground origins. Fleas on adults in one population (Oregon) had breeding ground isotopic signatures, as flea compositions did not differ from nestling feathers or toenails. Adult owls in Idaho had fleas that similarly did not express a wintering ground signature, but they were enriched in the heavy isotope (deuterium) relative to nestling feathers and toenails. Therefore, we discuss the possibility that adult owls in Idaho acquired fleas at migratory stopover sites. While the latter indicates that Burrowing Owls have the potential to disperse fleas, there was no evidence of continent-wide movement of fleas by owls from wintering grounds to breeding grounds.

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