The "Underworld" in a Territorial Sparrow: Adaptive Strategy for Floaters

Smith, Susan M.

doi:10.1086/283298

Cited by 267 publications

(161 citation statements)

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“…In particular, many populations of birds have a contingent of breeding age individuals that are thwarted from breeding by a shortage of resources, particularly territories. In many species, these individuals become floaters (i.e., presumed to roam in search of vacant territories) that tend to be behaviorally cryptic (Smith 1978, Stutchbury and Robertson 1985. There is some evidence that a proportion of floater Tree Swallows breed, but not to the same extent as regular box occupants (Lombardo 1988, Lifjeld et al 1993, Shutler and Clark 2003.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America

Shutler¹,

Hussell²,

Norris³

et al. 2012

ACE

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ABSTRACT. Data from the North American Breeding Bird Survey (BBS) suggest that populations of aerial insectivorous birds are declining, particularly in northeastern regions of the continent, and particularly since the mid-1980s. Species that use nest boxes, such as Tree Swallows (Tachycineta bicolor), may provide researchers with large data sets that better reveal finer-scale geographical patterns in population trends. We analyzed trends in occupancy rates for ca. 40,000 Tree Swallow nest-box-years from 16 sites across North America. The earliest site has been studied intensively since 1969 and the latest site since 2004. Nest box occupancy rates declined significantly at five of six (83%) sites east of -78° W longitude, whereas occupancy rates increased significantly at four of ten sites (40%) west of -78° W longitude. Decreasing box occupancy trends from the northeast were broadly consistent with aspects of a previous analysis of BBS data for Tree Swallows, but our finding of instances of increases in other parts of the continent are novel. Several questions remain, particularly with respect to causes of these broadscale geographic changes in population densities of Tree Swallows. The broad geographic patterns are consistent with a hypothesis of widespread changes in climate on wintering, migratory, or breeding areas that in turn may differentially affect populations of aerial insects, but other explanations are possible. It is also unclear whether these changes in occupancy rates reflect an increase or decrease in overall populations of Tree Swallows. Regardless, important conservation steps will be to unravel causes of changing populations of aerial insectivores in North America.RÉSUMÉ. Les données provenant du Relevé des oiseaux nicheurs (BBS) de l'Amérique du Nord semblent indiquer que les populations d'insectivores aériens sont en déclin, particulièrement dans les régions du nord-est du continent et depuis le milieu des années 1980. Grâce aux espèces qui utilisent les nichoirs, comme l'Hirondelle bicolore (Tachycineta bicolor), les chercheurs ont accès à une grande quantité de données qui révèlent davantage les tendances des populations à l'échelle fine. Nous avons analysé la tendance du taux d'occupation par l'Hirondelle bicolore à partir de 40 000 nichoirs-années provenant de 16 sites répartis en Amérique du Nord. Le site le plus ancien est suivi intensivement depuis 1969 et le plus récent, depuis 2004. Le taux d'occupation des nichoirs a diminué significativement dans 5 des 6 sites (83 %) situés à l'est du 78° de longitude ouest, tandis qu'il a augmenté significativement dans 4 des 10 sites (40 %) à l'ouest du 78° de longitude ouest. La tendance à la baisse de l'occupation observée dans le nord-est concorde dans les grandes lignes avec les résultats d'une analyse antérieure des données du BBS pour cette espèce, mais les hausses que nous avons observées dans d'autres régions de l'Amérique du Nord s'avèrent nouvelles. Plusieurs interrogations demeurent, notamment en ce qui a trait aux causes de ces chang...

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America

Shutler¹,

Hussell²,

Norris³

et al. 2012

ACE

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“…Furthermore, in any territorial species whose members establish stable home ranges in or near territorial neighbourhoods, individuals can repeatedly intrude into particular territories: examples include species in which neighbours regularly intrude into one another's territories (Temeles 1994;Gordon & Kulig 1996), or in which 'floaters' living in or near territorial neighbourhoods repeatedly intrude into nearby territories (e.g. Smith 1978;Arcese 1987;Stamps & Eason 1989;Rohner 1997). …”

Section:  2001 the Association For The Study Of Animal Behaviourmentioning

confidence: 99%

When should a territory resident attack?

2001

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Models of territorial defence tend to omit two characteristics of many territorial systems: repeated intrusions by the same individual and the learning processes of residents and intruders. Here we present state-dependent, dynamic models of feeding territories, designed to investigate temporal patterns of resident aggression towards intruders that are capable of spatial learning. We compare two types of models: (1) a nomadic intruder model, in which intruders never visit the same territory twice, and (2) a single, repeat intruder model, in which an intruder may repeatedly intrude into a given territory but is less likely to do so after being attacked. These two models produce qualitatively and quantitatively different patterns of aggression by residents. For instance, residents with intruders that may repeatedly intrude have high initial attack rates, regardless of initial probability of intrusion, but their attack rates decline over time. In contrast, residents in the nomadic intruder model do not attack intruders if intrusion rates are moderately high, and their attack rates are constant and high for most of the period of territory tenure. In addition, residents of both nomadic and repeat intruder scenarios stopped attacking intruders for a short period before voluntarily abandoning their feeding territories. The results of our models suggest that repeated intrusions and learning processes have a dramatic effect on territorial defence.  2001 The Association for the Study of Animal BehaviourFor many years, models have played an important role in advancing our understanding of the role of aggression in territorial species. However, a dichotomy has arisen between models investigating territories and models investigating aggressive behaviour. Most territory models focus on an individual versus the rest of the population, and consider such questions as when space should be defended, how much space should be defended, or what shape a territory should be (e.g.

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“…ad libitum. All previous studies of monitoring replacement in response to vacancies suggest that is ample time for replacement to occur (Smith 1978, Levin 1996. AU birds did well in captivity with no individuals losing weight.…”

Section: Methodsmentioning

confidence: 80%

“…Furthermore, floaters seem to confine their movements to include a maximum of 3-4 territories that brings them into close proximity of the territorial birds on a regular basis. Confined floating such as this allows the individual to benefit from knowledge of the terrain and potential mates and would also allow them to establish dominance relations with other floaters in the area (Smith 1978). Thus, floaters on a territory would be the first to detect the absence of the territory owner and, therefore, would have the first opportunity to settle into the newly created vacancy.…”

Section: Discussionmentioning

confidence: 99%

Territory Switching and Floating in White-Bellied Antbird (Myrmeciza longipes), a Resident Tropical Passerine in Panama

2004

The Auk

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ABSTRACT.•We investigated the yearlong territorial behavior of White-bellied Antbirds {Myrmeciza longipes) in Panama by conducting 17 experimental removals during the nonbreeding season on both sexes. We also monitored the territorial behavior and occupancy of 48 males and 34 females throughout the nonbreeding and breeding seasons. We tested the importance of territory switching, mate advertisement, foray behavior, and role of floaters. In seven of the removal experiments, both members of a pair were radiotagged and tracked throughout the duration of the experiments. It was predicted that widowed birds would attempt to attract a new mate through increased song rate or unique vocalizations; however, that behavior was not observed in White-bellied Antbirds. We documented a weak response in floaters to territorial vacancies and found that territory switching occurs regularly in response to experimental removals and naturally within populations. We found density of birds in an area influences the probability of replacement and is likely a reflection of territory quality given that birds in high-density areas were in better physical condition, spent less time off-territory, and competed more for those territories. Telemetry revealed that individuals made silent extraterritorial forays during the nonbreeding season. Birds could use those forays to assess the quality and status of neighboring territories and to find food during this period when food abundance is low. Several birds were observed to temporarily abandon territorial behavior for periods from 2 to 13 months, a previously undocumented behavior in this type of territorial system. RESUMEN.•Investigamos el comportamiento territorial de Myrmeciza longipes a lo largo del año en Panamá mediante 17 remociones experimentales en ambos sexos durante la estación no reproductiva. También monitoreamos el comportamiento territorial y la permanencia en los territorios de 48 machos y 34 hembras a lo largo de las estaciones reproductiva y no reproductiva. Evaluamos la importancia del cambio de territorios, el despliegue de apareamiento, el comportamiento de incursión y el rol de los individuos flotantes. En siete de los experimentos de remoción, ambos miembros de la pareja fueron marcados con radiotransmisores y seguidos a lo largo de los experimentos. Se predijo que las aves que enviudaron intentarían atraer una nueva pareja mediante incrementos en la tasa de cantos o mediante vocalizaciones únicas; sin embargo, este comportamiento no fue observado en M. longipes. Documentamos una respuesta débil en los individuos flotantes hacia los territorios vacantes y encontramos que el cambio de territorios ocurre regularmente como respuesta a las remociones experimentales y de modo natural en las poblaciones. Encontramos que la densidad de aves de un área influencia la probabilidad de reemplazo y probablemente refleja la calidad territorial dado que las aves en áreas de alta densidad estuvieron en mejor condición física, gastaron menos tiempo fuera del territorio y compitieron más p...

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The "Underworld" in a Territorial Sparrow: Adaptive Strategy for Floaters

Cited by 267 publications

References 5 publications

Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America

Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America

When should a territory resident attack?

Territory Switching and Floating in White-Bellied Antbird (Myrmeciza longipes), a Resident Tropical Passerine in Panama

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