Isotopic Evaluation of Interrupted Molt in Northern Breeding Populations of the 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.

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

The Auk ◽

10.1093/ornithology/ukaa072 ◽

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.

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Early Maize in Northeastern North America: A Comment on Emerson and Colleagues

American Antiquity ◽

10.1017/aaq.2020.93 ◽

2021 ◽

Vol 86 (2) ◽

pp. 425-427

Author(s):

John P. Hart ◽

William A. Lovis ◽

M. Anne Katzenberg

Keyword(s):

North America ◽

Great Lakes ◽

Empirical Evidence ◽

River Valley ◽

Human Bone ◽

Northeastern North America ◽

Isotopic Evidence ◽

St Lawrence River

Emerson and colleagues (2020) provide new isotopic evidence on directly dated human bone from the Greater Cahokia region. They conclude that maize was not adopted in the region prior to AD 900. Placing this result within the larger context of maize histories in northeastern North America, they suggest that evidence from the lower Great Lakes and St. Lawrence River valley for earlier maize is “enigmatic” and “perplexing.” Here, we review that evidence, accumulated over the course of several decades, and question why Emerson and colleagues felt the need to offer opinions on that evidence without providing any new contradictory empirical evidence for the region.

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Correction to: Winter home range and habitat selection differs among breeding populations of herring gulls in eastern North America

Movement Ecology ◽

10.1186/s40462-019-0157-5 ◽

2019 ◽

Vol 7 (1) ◽

Author(s):

Christine M. Anderson ◽

H. Grant Gilchrist ◽

Robert A. Ronconi ◽

Katherine R. Shlepr ◽

Daniel E. Clark ◽

...

Keyword(s):

Habitat Selection ◽

North America ◽

Home Range ◽

Eastern North America ◽

Herring Gulls ◽

Breeding Populations

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Malarial parasites as geographical markers in migratory birds?

Biology Letters ◽

10.1098/rsbl.2005.0429 ◽

2006 ◽

Vol 2 (2) ◽

pp. 213-216 ◽

Cited By ~ 31

Author(s):

Sylvia M Fallon ◽

Robert C Fleischer ◽

Gary R Graves

Keyword(s):

North America ◽

Migratory Birds ◽

Wide Distribution ◽

Specific Information ◽

Population Movements ◽

Site Specific ◽

Dendroica Caerulescens ◽

Bird Populations ◽

Breeding Populations ◽

Wintering Range

We tested the hypothesis that malarial parasites ( Plasmodium and Haemoproteus ) of black-throated blue warblers ( Dendroica caerulescens ) provide sufficient geographical signal to track population movements between the warbler's breeding and wintering habitats in North America. Our results from 1083 warblers sampled across the species' breeding range indicate that parasite lineages are geographically widespread and do not provide site-specific information. The wide distribution of malarial parasites probably reflects postnatal dispersal of their hosts as well as mixing of breeding populations on the wintering range. When compared to geographically structured parasites of sedentary Caribbean songbirds, patterns of malarial infections in black-throated blue warblers suggest that host–malaria dynamics of migratory and sedentary bird populations may be subject to contrasting selection pressures.

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Allometry of the Duration of Flight Feather Molt in Birds

PLoS Biology ◽

10.1371/journal.pbio.1000132 ◽

2009 ◽

Vol 7 (6) ◽

pp. e1000132 ◽

Cited By ~ 111

Author(s):

Sievert Rohwer ◽

Robert E. Ricklefs ◽

Vanya G. Rohwer ◽

Michelle M. Copple

Keyword(s):

Flight Feather ◽

Feather Molt

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The distribution, abundance and population trends of gentoo, rockhopper and king penguins in the Falkland Islands

Oryx ◽

10.1046/j.1365-3008.1998.d01-39.x ◽

1998 ◽

Vol 32 (3) ◽

pp. 223-232 ◽

Cited By ~ 4

Author(s):

M. Bingham

Keyword(s):

World Wide ◽

Austral Summer ◽

Population Trends ◽

King Penguin ◽

Falkland Islands ◽

Terrestrial Environment ◽

Breeding Populations ◽

Breeding Location ◽

Penguin Species

The Falkland Islands are a globally important breeding location for seabirds, including penguins. The total breeding populations of three of the four main penguin species present in the Falklands were censused in the austral summer of 1995/96. The results for gentoo and rockhopper penguins suggest declines of about 43 and 90 per cent, respectively, since a similar census in 1932/33. Recent monitoring studies suggest that these declines are still continuing; research to investigate causes (which is likely to reflect changes in the marine, rather than terrestrial environment) is a high priority. In contrast, king penguin populations, currently c. 400 pairs, have increased steadily, by 700 per cent since 1980/81, in line with world-wide trends for this species.

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Life History Implications of Complete and Incomplete Primary Molts in Pelagic Cormorants

The Condor ◽

10.1093/condor/103.3.555 ◽

2001 ◽

Vol 103 (3) ◽

pp. 555-569 ◽

Cited By ~ 1

Author(s):

Christopher E. Filardi ◽

Sievert Rohwer

Keyword(s):

Life History ◽

North America ◽

North American ◽

Northeastern Asia ◽

Flight Feather ◽

Historia De Vida

Abstract We describe the rules of primary flight-feather replacement for Pelagic Cormorants (Phalacrocorax pelagicus), and contrast the completeness of primary replacement in individuals from Asia and North America. In adult Pelagic Cormorants primary replacement is stepwise, with multiple waves of molt, each initiated at the innermost primary (P1), proceeding simultaneously toward the tip of the wing. Shugart and Rohwer's (1996) ontogenetic model for generating and maintaining stepwise primary replacement depended upon incomplete molts. In each new episode of molt, waves of primary replacement were thought to be initiated at P1 and at each arrested wave that had failed to replace all old feathers in the preceding molt. Because most adult Pelagic Cormorants from North America completely replace their primaries but maintain stepwise primary molts, the latter assumption must be relaxed. In contrast to the present-day situation in North America, Pelagic Cormorants from northeastern Asia have incomplete molts of their primaries, and may be forced to skip breeding in some years to clear their wings of overworn primaries. Young birds from Asia start the replacement of their juvenile primaries later than North American birds and replace more feathers simultaneously. Implicancias de la Muda Primaria Completa e Incompleta en la Historia de Vida de Phalacrocorax pelagicus Resumen. Describimos las reglas de reemplazo de plumas primarias para Phalacrocorax pelagicus y contrastamos la totalización del reemplazo de primarias entre individuos de Asia y América del Norte. En individuos adultos, el reemplazo de primarias ocurre en varias etapas, con múltiples secuencias de muda cada una iniciada en la primaria más interna (P1), procediendo simultáneamente hacia la punta del ala. El modelo ontogenético de Shugart y Rohwer (1996) para la generación y mantenimiento del reemplazo en etapas de las plumas primarias depende de mudas incompletas. Se pensaba que en cada nuevo episodio de muda las secuencias de reemplazo de primarias eran iniciadas en P1 y en cada punto de interrupción de la muda precedente que hubiera impedido el reemplazo de todas las plumas viejas. Debido a que la mayoría de los individuos adultos de P. pelagicus de Norteamérica reeemplazan completamente sus primarias pero aún lo hacen en etapas, la última suposición debe ser re-evaluada. En contraste con la situación actual en Norteamérica, individuos del noreste de Asia tienen mudas incompletas de sus primarias y pueden verse forzados a no reproducirse en algunos años para despojarse de la presencia de primarias desgastadas. Las aves juveniles de Asia comienzan el reemplazo de sus primarias más tarde y reemplazan más plumas simultáneamente que las aves de Norteamérica.

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