Bimodal orientation and the occurrence of temporary reverse bird migration during autumn in south Scandinavia

Åkesson, Susanne; Karlsson, Lennart; Wålinder, Göran; Alerstam, Thomas

doi:10.1007/s002650050245

Cited by 99 publications

(73 citation statements)

References 31 publications

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“…Early arrival may increase the potential for exposure to poor weather conditions such as late season snowstorms, low temperatures or extended periods of rain. Food limitation and/or poor environmental conditions may lead to substantial mortality (Dence 1946;Zumeta and Holmes 1978;Brown and Brown 2000), reverse migration (Alerstam 1978;Terrill and Ohmart 1984;Akesson et al 1996), or to shifts in foraging behavior as birds attempt to overcome food limitation and offset increased thermoregulatory requirements (Zumeta and Holmes 1978;Martin and Karr 1990). As migrants encounter unfavorable circumstances during this early transition period, fat stores accumulated during passage would serve to overcome unpredictable foraging situations (see Møller 1994), sustaining an individual until the environment becomes more suitable.…”

Section: Fat and Early Arrivalmentioning

confidence: 98%

Arrival fat and reproductive performance in a long-distance passerine migrant

2003

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Long-distance passerine migrants deposit substantial fat stores to fuel their migratory journey. Many of those migratory birds arrive at their northerly breeding grounds with larger fat stores than were necessary to reach their breeding area. Both male and female American Redstarts ( Setophaga ruticilla) arrived to breed in Michigan's Upper Peninsula with fat, and females arrived with more fat than males in 2 out of 3 years. We test the hypothesis that migrants arriving at the breeding grounds with more body fat have higher reproductive success than birds arriving with little or no fat. Females, and to a lesser extent males, that arrive with fat experience gains in reproductive performance as evidenced by increased clutch size, egg volume, and nestling mass. The results have implications for understanding how events occurring during one phase of the annual cycle influence survival and/or reproductive performance in subsequent phases.

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Section: Fat and Early Arrivalmentioning

confidence: 98%

Arrival fat and reproductive performance in a long-distance passerine migrant

2003

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“…Sandberg et al, 1988;Busse, 1987;Åkesson et al, 1996;Mouritsen, 1998;Muheim et al, 2002;Remisiewicz, 2002). In most studies, standard procedures are deployed to treat the circular cage data from individuals for further statistical analyses (e.g.…”

Section: Discussionmentioning

confidence: 99%

A new approach to evaluate multimodal orientation behaviour of migratory passerine birds recorded in circular orientation cages

Ożarowska

Ilieva

Zehtindjiev

et al. 2013

Journal of Experimental Biology

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SUMMARYCircular orientation cages have been used for several decades to record the migratory orientation of passerine migrants, and have been central to the investigation of the functional characteristics of the biological compasses used for orientation. The use of these cages offers unique possibilities to study the migratory behaviour of songbirds, but suffers from statistical limitations in evaluating the directions of the activity recorded in the cages. The migratory activity has been reported to vary, including complex multimodal orientation of migratory passerines tested in orientation cages irrespective of species studied. The currently applied circular statistical methods fail to describe orientation responses differing from unimodal and axial distributions. We propose for the first time a modelling procedure enabling the analysis of multimodal distributions at either an individual or a group level. In this paper we compare the results of conventional methods and the recommended modelling approach. Migratory routes may be more complex than a simple migratory direction, and multimodal behaviour in migratory species at the individual and population levels can be advantageous. Individuals may select the expected migratory direction, but may also return to safer sites en route, i.e. sites already known, which provide food and/or shelter in reverse directions. In individual birds, several directions may be expressed in the same test hour. At the species level, multimodal orientation may give an opportunity to expand the range or may refer to differential migration route preferences in different populations of birds. A conflicting experimental situation may also result in a different preferential orientation. In this paper we suggest a statistical solution to deal with these types of variations in orientation preference.

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“…Instead, they demonstrated a unique windrelated orientation, which to our knowledge has not been previously reported by orientation experiments. Although reverse migration has been reported in lean birds looking for a refuelling site (Åkesson et al 1996a;Sandberg et al 2002;Deutschlander and Muheim 2009), we suspect that the Great Knots headed SE in the funnels in response to the wind rather than to a food shortage for the following reasons. First, flying in a reverse direction to obtain food seems unlikely at both CMDT and YLE.…”

Section: Orientationmentioning

confidence: 99%

“…According to their migratory situation and to the characteristics of stopover sites, birds might exhibit migratory motivation differently among sites, i.e., the relationship between migratory restlessness and various factors may differ among sites. For example, energetic condition usually takes precedence when birds are confronted with an ecological barrier, thus they will suppress migratory restlessness and even perform temporary reverse migration unless enough fuel is stored (Åkesson et al 1996a;Åkesson 1999;Sandberg et al 2002). However, at sites with refuelling possibilities ahead closely, migratory motivation of birds might not be necessarily associated with fuel stores (Åkesson 1999;Tsvey et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Springtime migratory restlessness and departure orientation of Great Knots (Calidris tenuirostris) in the south compared to the north Yellow Sea

et al. 2017

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Background:The motivation of birds to proceed with migration is associated with both endogenous and exogenous factors. According to their migratory situation and to the characteristics of stopover sites, birds might exhibit migratory motivation differently among sites. Although migratory motivation of migrating birds has been well studied in many species, the investigation of the same species in different migratory situations and at different stopover sites is still limited. We predicted that birds at different stopover sites could differ in migratory disposition, including expression of migratory restlessness and responses to environmental cues. Methods:Here we compared migration motivation and orientation of Great Knots (Calidris tenuirostris) at two stopover sites, Chongming Dongtan in the south Yellow Sea, which is a temporary rest site, and Yalujiang Estuary Wetland in the north Yellow Sea, which is a critical refuelling site, during northward migration. Modified Emlen funnels, with thermal paper inside to record scratches of the birds, were used to detect activity (intensity and direction) of birds. Environmental conditions, including wind direction and speed, cloud cover, tide condition, times of the day (before and after sunset) were recorded during experiments. Generalized linear models were used to detect the effects of endogenous and exogenous factors on the migratory motivation of the birds. Results:In the south Yellow Sea, the migratory activity intensity of Great Knots was positively related to wind assistance. In the north Yellow Sea, where birds exhibited higher intensity of migratory activity than in the south, the intensity increased and the motivation to initiate migration grew stronger as the season advanced. The Great Knots exhibited wind-related orientation behaviour in the funnels at both sites. Conclusions:The results suggest that the intensity of migratory motivation differed between the two sites. Departure decisions of Great Knots appear to be affected mainly by external factors at the temporary rest site in the south Yellow Sea but possibly by endogenous factors at the final pre-breeding refuelling site in the north Yellow Sea.

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Bimodal orientation and the occurrence of temporary reverse bird migration during autumn in south Scandinavia

Cited by 99 publications

References 31 publications

Arrival fat and reproductive performance in a long-distance passerine migrant

Arrival fat and reproductive performance in a long-distance passerine migrant

A new approach to evaluate multimodal orientation behaviour of migratory passerine birds recorded in circular orientation cages

Springtime migratory restlessness and departure orientation of Great Knots (Calidris tenuirostris) in the south compared to the north Yellow Sea

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