scholarly journals High-intensity flight feather molt and comparative molt ecology of warblers of eastern North America

The Auk ◽  
2021 ◽  
Vol 138 (1) ◽  
Author(s):  
Ronald L Mumme ◽  
Robert S Mulvihill ◽  
David Norman
Keyword(s):  
North America ◽  
Parental Care ◽  
High Intensity ◽  
Bird Species ◽  
Late Summer ◽  
Positive Association ◽  
Eastern North America ◽  
Surprising Result ◽  
Flight Feather ◽  
Feather Molt

Abstract Rapid high-intensity molt of flight feathers occurs in many bird species and can have several detrimental consequences, including reductions in flight capabilities, foraging performance, parental care, and plumage quality. Many migratory New World warblers (family Parulidae) are known to have intense remigial molt, and recent work has suggested that simultaneous replacement of the rectrices may be widespread in the family as well. However, the phylogenetic distribution of simultaneous rectrix molt, and high-intensity flight feather molt more generally, has not been systematically investigated in warblers. We addressed this issue by examining flight feather molt in 13 species, representing 7 different warbler genera, at Powdermill Avian Research Center in southwestern Pennsylvania, USA. All 13 species replaced their 12 rectrices simultaneously, with the onset of rectrix molt occurring in the early-middle stages of high-intensity primary molt. As expected, single-brooded early migrants molted earlier than double-brooded species whose nesting activities extend into late summer. However, our finding that late-molting species replaced their primaries more slowly and less intensively than early molting species was unexpected, as late-molting species are widely hypothesized to be under stronger migration-related time constraints. This surprising result appears to be at least partially explained by a positive association between the pace of molt and daylength; shorter late-summer days may mandate reduced daily food intake, lower molt intensity, and a slower pace of molt. In comparison to other passerines, flight feather molt in warblers of eastern North America is extraordinarily intense; at its peak, individuals are simultaneously replacing 50–67% of their 48 flight feathers (all 12 rectrices and 6–10 remiges on each wing) for 2–3 weeks or more. Because molt of this intensity is likely to present numerous challenges for flight, avoiding predators, foraging, and parental care, the period of flight feather molt for warblers constitutes a highly demanding phase of their annual cycle.

scholarly journals Tracking multi-generational colonization of the breeding grounds by monarch butterflies in eastern North America

2013 ◽  
Vol 280 (1768) ◽  
pp. 20131087 ◽  
Author(s):  
D. T. Tyler Flockhart ◽  
Leonard I. Wassenaar ◽  
Tara G. Martin ◽  
Keith A. Hobson ◽  
Michael B. Wunder ◽  
...  
Keyword(s):  
North America ◽  
Danaus Plexippus ◽  
Late Summer ◽  
Breeding Habitat ◽  
Eastern North America ◽  
Distribution Models ◽  
Monarch Butterflies ◽  
Breeding Distribution ◽  
Breeding Grounds ◽  
Isotope Measurements

Insect migration may involve movements over multiple breeding generations at continental scales, resulting in formidable challenges to their conservation and management. Using distribution models generated from citizen scientist occurrence data and stable-carbon and -hydrogen isotope measurements, we tracked multi-generational colonization of the breeding grounds of monarch butterflies ( Danaus plexippus ) in eastern North America. We found that monarch breeding occurrence was best modelled with geographical and climatic variables resulting in an annual breeding distribution of greater than 12 million km 2 that encompassed 99% occurrence probability. Combining occurrence models with stable isotope measurements to estimate natal origin, we show that butterflies which overwintered in Mexico came from a wide breeding distribution, including southern portions of the range. There was a clear northward progression of monarchs over successive generations from May until August when reproductive butterflies began to change direction and moved south. Fifth-generation individuals breeding in Texas in the late summer/autumn tended to originate from northern breeding areas rather than regions further south. Although the Midwest was the most productive area during the breeding season, monarchs that re-colonized the Midwest were produced largely in Texas, suggesting that conserving breeding habitat in the Midwest alone is insufficient to ensure long-term persistence of the monarch butterfly population in eastern North America.

scholarly journals Ecology of Eastern Equine Encephalitis Virus in the Southeastern United States: Incriminating Vector and Host Species Responsible for Virus Amplification, Persistence, and Dispersal

2021 ◽  
Author(s):  
Nathan D Burkett-Cadena ◽  
Jonathan F Day ◽  
Thomas R Unnasch
Keyword(s):  
North America ◽  
Phylogenetic Analyses ◽  
Mosquito Species ◽  
Severe Disease ◽  
Bird Species ◽  
Encephalitis Virus ◽  
Eastern North America ◽  
Eastern Equine Encephalitis Virus ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus

Abstract Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is a mosquito-borne pathogen found in eastern North America that causes severe disease in humans and horses. The mosquito Culiseta melanura (Coquillett) (Diptera: Culicidae) is the primary enzootic vector of EEEV throughout eastern North America while several mosquito species belonging to diverse genera serve as bridge vectors. The ecology of EEEV differs between northern and southern foci, with respect to phenology of outbreaks, important vertebrate hosts, and bridge vector species. Active transmission is limited to roughly half of the year in northern foci (New York, New Hampshire, Massachusetts, Connecticut), while year-round transmission occurs in the southeastern region (particularly Florida). Multiple phylogenetic analyses indicate that EEEV strains circulating in northern foci are likely transported from southern foci by migrating birds. Bird species that overwinter or migrate through Florida, are bitten by Cs. melanura in late spring, and arrive at northern breeding grounds in May are the most likely candidates to disperse EEEV northward. Available data indicate that common yellowthroat and green heron satisfy these criteria and could serve as virus dispersers. Understanding the factors that drive the phenology of Cs. melanura reproduction in the south and the timing of avian migration from southern foci could provide insight into how confluence of these biological phenomena shapes outbreaks of EEE throughout its range. This information could be used to develop models predicting the likelihood of outbreaks in a given year, allowing vector control districts to more efficiently marshal resources necessary to protect their stakeholders.

scholarly journals Isotopic Evaluation of Interrupted Molt in Northern Breeding Populations of the Loggerhead Shrike

The Condor ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 877-886 ◽  
Author(s):  
Guillermo E. Pérez ◽  
Keith A. Hobson
Keyword(s):  
North America ◽  
Isotope Analysis ◽  
Southern Region ◽  
Flight Feather ◽  
Isotopic Evidence ◽  
Breeding Populations ◽  
Breeding Location ◽  
Feather Molt ◽  
Loggerhead Shrike

Abstract Abstract The Loggerhead Shrike (Laniusludovicianus) breedsthroughout North America and various populationsapparently exhibit diverse molt strategies.However, molt in this species and how it may varygeographically is generally poorly known. Weinvestigated molt sequence in 27 breedingLoggerhead Shrikes using stable hydrogen(δD) isotope analysis of flightfeathers. Because feather δD varies with thelatitude at which feathers are grown in NorthAmerica, it is relatively straightforward toidentify those feathers grown south of anindividual's breeding location. We sampled 11feathers per individual to evaluate locations offeather molt between breeding and wintering groundsin North America. Sampling took place in centralSaskatchewan, Canada (n =  18 individuals) andin the southern region of the Saskatchewan-Manitobaborder (n =  9). We found evidencethat shrikes initiated flight feather molt on theirbreeding grounds (P1 and P3) but thenlargely suspended molt until reaching theirwintering areas. The isotopic evidence suggeststhat the first primary (P1, most depleted indeuterium, mean  = −103‰) provides information onshrike breeding latitudes while the innermosttertial (S9, most enriched in deuterium, mean =  −49‰)provides information on shrike wintering orsouthernmost molting latitudes.

Experimentally increased costs of parental care are shunted to offspring in species with extended care

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Parental Care ◽  
Total Duration ◽  
Bird Species ◽  
Life History Strategy ◽  
Experimental Treatment ◽  
Cost Of Care ◽  
Adult Survival ◽  
Supporting Evidence ◽  
Trade Offs

Biparental care systems are a valuable model to examine conflict, cooperation, and coordination between unrelated individuals, as the product of the interactions between the parents influences the fitness of both individuals. A common experimental technique for testing coordinated responses to changes in the costs of parental care is to temporarily handicap one parent, inducing a higher cost of providing care. However, dissimilarity in experimental designs of these studies has hindered interspecific comparisons of the patterns of cost distribution between parents and offspring. Here we apply a comparative experimental approach by handicapping a parent at nests of five bird species using the same experimental treatment. In some species, a decrease in care by a handicapped parent was compensated by its partner, while in others the increased costs of care were shunted to the offspring. Parental responses to an increased cost of care primarily depended on the total duration of care that offspring require. However, life history pace (i.e., adult survival and fecundity) did not influence parental decisions when faced with a higher cost of caring. Our study highlights that a greater attention to intergenerational trade-offs is warranted, particularly in species with a large burden of parental care. Moreover, we demonstrate that parental care decisions may be weighed more against physiological workload constraints than against future prospects of reproduction, supporting evidence that avian species may devote comparable amounts of energy into survival, regardless of life history strategy.

The Identification and Study of Indian Shell Middens in Eastern North America: 1643–1861

1986 ◽  
Vol 6 (3) ◽  
pp. 227-243 ◽  
Author(s):  
Andrew L. Christenson
Keyword(s):  
Nineteenth Century ◽  
Civil War ◽  
North America ◽  
East Coast ◽  
Eastern North America ◽  
Shell Midden ◽  
Shell Middens ◽  
Work Done

Although the interest in shell middens in North America is often traced to reports of the discoveries in Danish kjoekkenmoeddings in the mid-nineteenth century, extensive shell midden studies were already occurring on the East Coast by that time. This article reviews selected examples of this early work done by geologists and naturalists, which served as a foundation for shell midden studies by archaeologists after the Civil War.

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