Untersuchungen zur Jahresperiodik von Laubsängern

Gwinner, Eberhard

doi:10.1007/bf01671132

Cited by 44 publications

(13 citation statements)

References 7 publications

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“…Reduced plasticity was selective: As soon as molt started, Siberian stonechats developed strong responses to hatching date. Inflexible, early molt onset and subsequent increases in photoperiodic responsiveness, reported from the field and experimental studies, could indeed represent a typical strategy of long‐distance migrants 1,2,11,30. Initial reliance on endogenous clocks could provide a safety measure securing timely preparation for departure in birds from highly predictable but time‐constrained habitats.…”

Section: Discussionmentioning

confidence: 96%

“…Figure 7 shows age at commencing nocturnal restlessness in relation to hatching date. The only difference between the subspecies was an overall earlier Zugunruhe onset in Siberian stonechats, typical of lon‐distance migrants 1–3,10. Remarkably, calendar effects were identical among the subspecies, independently of their native grounds and migratory behavior.…”

Section: Commencing Migratory Restlessnessmentioning

confidence: 90%

“…In the field and in captivity, long‐distance migrants were observed to show little variation in the timing of breeding, molt, and migratory activities. They typically responded less strongly to environmental perturbation and manipulation of temporal cues than did related, less migratory taxa 1–7. Rigid schedules are therefore among candidate traits for “adaptive migratory syndromes.” Avian seasonal timing, in turn, has been shown to involve endogenous clocks supplemented by additional information 4–10.…”

Section: Rigid Schedules Of Long‐distance Migrants?mentioning

confidence: 99%

“…Speeding up molt late in the season, termed “calendar effect,” is thought to allow lat‐hatched young to prepare for timely migration and wintering 3,11,30. Calendar effects function via day length perceived by nestlings and can be simulated in captivity 2,11. Birds breeding at higher latitudes, typically under predictable seasonality, are thought to rely particularly on day length cues for timing seasonal behavior 4–7.…”

Section: Timing Postjuvenile Molt: Cue Use Differentiationmentioning

confidence: 99%

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Flexible Seasonal Timing and Migratory Behavior: Results from Stonechat Breeding Programs

Helm

Gwinner

Trost

2005

Annals of the New York Academy of Sciences

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Rigid schedules of long-distance migrants could be among candidate traits for adaptive migratory syndromes. This prediction was tested on stonechats, passerines that differ widely in migratory behavior and seasonal schedules. Stonechats in Europe are short-distance migrants and multiclutched, whereas African residents and Siberian long-distance migrants usually raise single broods. In captivity, all subspecies displayed endogenous cycles of reproductive development and molt. The subspecies differed in time afforded to life cycle stages. Under conducive aviary conditions, African stonechats were multibrooded, whereas Siberian stonechats did not add clutches. This difference in flexibility was exclusively related to the length of breeding windows. Stonechats also differed in premigratory preparations. Postjuvenile molt started early in Siberian stonechats, but in European and African stonechats, depended strongly on hatching date. In contrast, all subspecies shortened molt duration at the same rate when hatched from late broods. Plasticity of Zugunruhe timing was identical in Siberian and European subspecies and nearly compensated for hatching late. The stonechat data suggest a refined understanding of temporal plasticity in long-distance migrants. Overall, plasticity was not reduced, but was differently organized. Apparently rigid migrant schedules were related to short breeding cycles and inflexible molt onset. Short windows for breeding and juvenile development could provide safety measures for timely departure. Once molt was initiated, temporal plasticity of long-distance migrants matched that of less migratory conspecifics. In addition to adjusting endogenous programs, stonechats differed in implementing them in the field. Modifying the conditions under which programs are expressed may be an efficient way to enhance seasonal plasticity.

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Section: Discussionmentioning

confidence: 96%

Section: Commencing Migratory Restlessnessmentioning

confidence: 90%

Section: Rigid Schedules Of Long‐distance Migrants?mentioning

confidence: 99%

Section: Timing Postjuvenile Molt: Cue Use Differentiationmentioning

confidence: 99%

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Flexible Seasonal Timing and Migratory Behavior: Results from Stonechat Breeding Programs

Helm

Gwinner

Trost

2005

Annals of the New York Academy of Sciences

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“…However, it was not until the 1930s that experimental techniques were developed to quantify the activity of caged birds, by Wagner () and Palmgren (; see also reviews by Dorst , Berthold ), making it possible to investigate how the migratory restlessness (‘Zugunruhe’) is determined by endogenous and environmental (food, weather, photoperiod) factors. This technique of recording activity patterns of caged migratory birds for several years paved the way for major discoveries of the circannual rhythms in different species of long‐ and short‐distance songbird migrants by Gwinner (, ; reviewed by Gwinner , , Gwinner and Helm ) and Berthold (; reviewed by Berthold , ). The assumption that migratory restlessness reflect motivation to depart on migratory flights has been confirmed by correlations between birds’ restlessness in cages and their behaviour in the field with respect to departure probability (Eikenaar et al ) and response to wind (Eikenaar and Schmaljohann ).…”

mentioning

confidence: 99%

Activity and migratory flights of individual free‐flying songbirds throughout the annual cycle: method and first case study

Bäckman

Andersson

Alerstam

et al. 2016

Journal of Avian Biology

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We describe a method and device ( 1.2 g) for recording, processing and storing data about activity and location of individuals of free-living songbirds throughout the annual cycle.Activity level was determined every five minutes from five 100 ms samples of accelerometer data with 5 s between the sampling events. Activity levels were stored on an hourly basis throughout the annual cycle, allowing periods of resting/sleep, continuous flight and intermediate activity (foraging, breeding) to be distinguished. Measurements from a light sensor were stored from preprogrammed key stationary periods during the year to provide control information about geographic location.Successful results, including annual actogram, were obtained for a red-backed shrike Lanius collurio carrying out its annual loop migration between northern Europe and southern Africa. The shrike completed its annual migration by performing  66 (max. 73) nocturnal migratory flights (29 flights in autumn and  37, max. 44, in spring) adding up to a total of  434 (max. 495) flight hours. Migratory flights lasted on average 6.6 h with maximum 15.9 h. These flights were aggregated into eight travel episodes (periods of 4-11 nights when flights took place on the majority of nights). Daytime resting levels were much higher during the winter period compared to breeding and final part of spring migration. Daytime resting showed peaks during days between successive nocturnal flights across Sahara, continental Africa and the Arabian Peninsula, indicating that the bird was mostly sleeping between these long migratory flights.Annual activity and flight data for free-living songbirds will open up many new research possibilities. Main topics that can be addressed are e.g. migratory flight performance (total flight investment, numbers and characteristics of flights), timing of stationary periods, activity patterns (resting/sleep, activity level) in different phases of the annual cycle and variability in the annual activity patterns between and within individuals.

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Energetics of Winter and Migratory Fattening

Biebach¹

1996

Avian Energetics and Nutritional Ecology

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Untersuchungen zur Jahresperiodik von Laubsängern

Cited by 44 publications

References 7 publications

Flexible Seasonal Timing and Migratory Behavior: Results from Stonechat Breeding Programs

Flexible Seasonal Timing and Migratory Behavior: Results from Stonechat Breeding Programs

Activity and migratory flights of individual free‐flying songbirds throughout the annual cycle: method and first case study

Energetics of Winter and Migratory Fattening

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