scholarly journals Wing Morphology and Flight Behavior of Some North American Hummingbird Species

The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 872-886 ◽  
Author(s):  
F. Gary Stiles ◽  
Douglas L. Altshuler ◽  
Robert Dudley
Keyword(s):  
Breeding Season ◽  
North American ◽  
Theoretical Models ◽  
Wing Disc ◽  
Territorial Behavior ◽  
Flight Behavior ◽  
Adult Males ◽  
Wing Morphology ◽  
Reversed Sexual Size Dimorphism ◽  
Species Specific

Abstract We explored the relationship between wing morphology and flight behavior with respect to sex and age in five species of North American hummingbirds. We first measured the length, chord or “width,“ and area of entire hummingbird wing planforms. We then calculated additional parameters of wing shape and size, including aspect and shape ratios, degree of taper or “pointedness,“ wing loading, and wing disc loading (WDL). Wings of adult males are not only shorter but also more narrow and tapered than those of adult or immature females; immature males have larger wings and lower WDL, more like those of females. A proposed relationship between WDL and territorial behavior and dominance is not supported, given that adult and immature males show similar feeding territoriality outside the breeding season but females rarely do. The more extreme and divergent wings of adult males probably reflect sexual selection in connection with aerial displays that include species-specific sound effects given during the breeding season. North American species are unusual among hummingbirds in showing reversed sexual size-dimorphism (males smaller, with relatively shorter wings), a feature shared with some other small hummingbirds, notably the “Pygmornis“ hermits. Attempts to explain hummingbird foraging and territorial behavior on the basis of differences in WDL have failed because many aspects of wing morphology, physiology, and flight behavior were not taken into account. Several wing parameters appear more related to other modes of flight than to strategies of nectar exploitation, and the morphology of any given wing represents a compromise between the often conflicting aerodynamic demands of different flight modes. Understanding hummingbird flight will require broad comparative studies of wing morphology and wingbeat kinematics in relation to flight behavior, and new theoretical models and experimental data will be needed to elucidate physiological and aerodynamic mechanisms underlying forward flight and maneuvering. Morfología Alar y Comportamiento de Vuelo de Unas Especies de Colibríes de Norteamérica

Economics of Breeding Territoriality in Male Calliope Hummingbirds

The Auk ◽  
1987 ◽  
Vol 104 (2) ◽  
pp. 242-253 ◽  
Author(s):  
Doug P. Armstrong
Keyword(s):  
Breeding Season ◽  
North American ◽  
Energy Resources ◽  
Territorial Behavior ◽  
High Quality ◽  
Potential Benefits ◽  
Stellula Calliope ◽  
Lines Of Evidence ◽  
Nectar Availability

Abstract Several lines of evidence indicate that the territorial behavior of postbreeding North American hummingbirds can be explained in primarily energetic terms. The territoriality of breeding males, however, may be different in that it may play an important role in courtship. The results of this study on breeding male Calliope Hummingbirds (Stellula calliope) indicated that territoriality could not be explained either directly or indirectly in terms of defense of energy resources. Throughout the 2-month breeding season, flower sampling indicated that males could have obtained energy faster by foraging on nearby undefended areas than by foraging on their territories. In June there were no profitable flowers on the territories, and males did all or nearly all of their foraging away from their territories. In May, when territory nectar availability was fairly high, males did not leave, expand, or shift their territories in response to experimental exclosure of all profitable flowers on those territories. I suggest that males may have preferentially selected territory sites with prominent perches near females' nesting areas, and that these considerations outweighed the potential benefits of defending territories on areas with high-quality nectar resources.

scholarly journals WING MORPHOLOGY AND FLIGHT BEHAVIOR OF SOME NORTH AMERICAN HUMMINGBIRD SPECIES

The Auk ◽  
2005 ◽  
Vol 122 (3) ◽  
pp. 872 ◽  
Author(s):  
F. Gary Stiles ◽  
Douglas L. Altshuler ◽  
Robert Dudley
Keyword(s):  
North American ◽  
Flight Behavior ◽  
Wing Morphology

Breeding ecology of the fairy martin

1999 ◽  
Vol 47 (5) ◽  
pp. 463 ◽  
Author(s):  
Michael J. L. Magrath
Keyword(s):  
Breeding Season ◽  
Weather Conditions ◽  
Adult Mortality ◽  
First Year ◽  
Breeding Ecology ◽  
Adult Males ◽  
Annual Productivity ◽  
Adverse Weather ◽  
Colony Site ◽  
The One

The breeding biology of the fairy martin, Hirundo ariel, was studied over three years (1992–95) in the Yarra Valley, Victoria. Adult males and females in this population were morphologically similar, though only females acquired a brood patch during the breeding season. Colonies ranged in size from 8 to 29 nests. Birds arrived in the study area in September and usually commenced laying in October, though nesting activities were generally asynchronous both between and within colonies. Most colonies contained active nests until February. At least 16% of adults and 5% of fledglings, on average, returned to the study area in the following year. Returning adults generally nested at the same colony site as the previous year, while most first-year birds nested at sites other than their natal colony. Adult males were more likely to return than adult females. Clutch size ranged from 2 to 5, with a mean of 3.5, and declined over the season. The incubation period varied from 12 to 18 days with a mean of 13.7. A mean of 1.8 chicks fledged per completed clutch, while 60% of clutches produced at least one chick. The period from hatching to fledging varied from 17 to 32 days, with a mean of 22.1, and increased with brood size. Fledging success was highest during the middle of the breeding season. Adverse weather conditions, resulting in the abandonment of clutch and brood, were the most common cause of nest failure, and on several occasions also resulted in adult mortality. Almost half the breeding females produced at least two clutches in the one season. Pairs produced from 0 to 8 fledglings per season, with those that commenced nesting earlier in the season having higher annual productivity. These results are discussed in relation to the breeding ecology of other members of the Hirundinidae.

Evidence for LH-inhibiting activity in ovine peripheral and testicular blood

1990 ◽  
Vol 123 (3) ◽  
pp. 345-352 ◽  
Author(s):  
V. Papapdopoulos ◽  
P. Kamtchouing ◽  
N. Boujrad ◽  
C. Pisselet ◽  
C. Perreau ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Breeding Season ◽  
Specific Binding ◽  
Apparent Molecular Weight ◽  
Rete Testis ◽  
Arterial Blood ◽  
Inhibiting Factor ◽  
Arterial Plasma ◽  
Species Specific ◽  
Venous Plasma

Abstract. Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 μg/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season. The addition of peripheral plasma leads to a testosterone production equal to 35 and 65% of the oLH-stimulated values, respectively, for ram blood collected in non-breeding and breeding seasons. The same concentration of ovine testicular lymph or rete testis fluid is without significant effect on cyclic AMP production; however, testosterone is slightly decreased by lymph but enhanced by rete testis fluid. Increasing amounts of venous or arterial testicular blood induce a dose-related decrease of the specific binding of labelled hCG in both rat and ram testicular membranes. This inhibiting factor is present in peripheral and testicular blood of either control or hypophysectomized or castrated rams, is a protein in nature, heat-sensitive, and has an apparent molecular weight higher than 10 000 daltons. These results suggest the existence of a control of LH-specific binding to its receptors and of Leydig cell cyclic AMP and testosterone outputs; these activities are not species-specific and are more concentrated in testicular venous than in arterial blood. The origin of this inhibiting factor remains to be determined, since it is not confined to the testis and not of pituitary origin.

DISTINGUISHING EXTERNAL FEATURES OF ADULT MALES AND FEMALES OF NORTH AMERICAN SPECIES OF PHYMATOCERA DAHLBOM (HYMENOPTERA: TENTHREDINIDAE) AND THEIR PHYLOGENY

1981 ◽  
Vol 113 (9) ◽  
pp. 801-806
Author(s):  
Henri Goulet
Keyword(s):  
North American ◽  
North American Species ◽  
Junior Synonym ◽  
Adult Males ◽  
Males And Females

AbstractDiscovery of new external structures permit easier separation of species of Phymatocera for both sexes. A key is given and a phylogeny is reconstructed for all species. The name P. rusculla (MacGillivray) is a junior synonym of P. offensa (MacGillivray).

Space fit for a king: spatial ecology of king cobras (Ophiophagus hannah) in Sakaerat Biosphere Reserve, Northeastern Thailand

2019 ◽  
Vol 40 (2) ◽  
pp. 163-178 ◽  
Author(s):  
Benjamin Michael Marshall ◽  
Colin Thomas Strine ◽  
Max Dolton Jones ◽  
Taksin Artchawakom ◽  
Ines Silva ◽  
...  
Keyword(s):  
Habitat Use ◽  
Breeding Season ◽  
Protected Area ◽  
Spatial Ecology ◽  
Radio Telemetry ◽  
Biosphere Reserve ◽  
Adult Males ◽  
Anthropogenic Pressures ◽  
Anthropogenic Landscapes ◽  
Ophiophagus Hannah

Abstract A species’ spatial ecology has direct implications for that species’ conservation. Far-ranging species may be more difficult to conserve because their movements increase their chances of encountering humans. The movements can take them out of protected areas, which is especially risky for species that are routinely persecuted. The king cobra (Ophiophagus hannah), a large venomous elapid, is subject to anthropogenic pressures, such as persecution and habitat loss. Here we present results from a study using radio telemetry to quantify movements and habitat use of nine king cobras in and around a protected area in Northeast Thailand. This study is the first investigation into the movements and habitat use of king cobras outside of the Western Ghats, India. On average, the tracked king cobra’s use areas of 493.42 ± 335.60 ha (95% fixed kernel), moving 183.24 ± 82.63 m per day. King cobras did not remain in intact forested area. Five of the individuals frequently used the human-dominated agricultural areas surrounding the protected area, appearing to make regular use of irrigation canals. Two adult males showed increases in movements during the breeding season. One male’s increased breeding season range caused him to venture beyond the protected area, shifting his habitat use from intact forests to scrub in human-dominated areas. King cobras’ large home range and willingness to use anthropogenic landscapes merits special consideration from conservation planners.

Not only big bulls. Correlation between morphometry, reproductive success, and testosterone level in a flooded savannah population of the spectacled caiman (Caiman crocodilus)

2021 ◽  
Author(s):  
Leidy Alejandra Barragan Contreras ◽  
Rafael Antelo ◽  
Adolfo Amezquita
Keyword(s):  
Reproductive Success ◽  
Breeding Season ◽  
Steroid Hormone ◽  
Multiple Paternity ◽  
Adult Males ◽  
Behavioral Traits ◽  
Testosterone Levels ◽  
Caiman Crocodilus ◽  
Paternity Tests ◽  
Hourly Basis

Testosterone is a steroid hormone involved in the expression of many morphological, physiological, and behavioral traits that arguably affect reproductive success. The evidence for that link is, however, incomplete or absent in the research on crocodylian species. Testosterone levels are also known to change throughout the breeding season, often on an hourly basis, which may further complicate studying their relationship with breeding success. We tested here whether baseline testosterone levels, measured out of the breeding season, are correlated with morphometry and reproductive success in Caiman crocodilus (LINNAEUS, 1758). Paternity tests, based on the amplification and genotyping of eight fluorochrome labeled microsatellites, failed to support a continuous relationship between these variables. Although adult males of all sizes contribute to reproduction, paternity was overrepresented in a few males with high values of maleness index (bigger males), supporting a despotic or pyramidal hierarchy among males. Maternity assignments supported the existence of multiple paternity, a phenomenon previously attributed in this species to the lack of large males caused by human hunting. The idea of larger males having more offspring is widespread in crocodylians, but to our knowledge, this is the first investigation that prove this dogma.

scholarly journals Relationship Among Breeding, Molting, and Wintering Areas of Male Barrow's Goldeneyes (Bucephala Islandica) in Eastern North America

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 676-684 ◽  
Author(s):  
Michel Robert ◽  
Réjean Benoit ◽  
Jean-Pierre L. Savard
Keyword(s):  
North American ◽  
River Estuary ◽  
North American Population ◽  
American Population ◽  
Adult Males ◽  
Breeding Area ◽  
The North ◽  
Bucephala Islandica ◽  
The Mean ◽  
St Lawrence River

Abstract Little is known of the eastern North American population of Barrow's Goldeneyes (Bucephala islandica), which was recently listed as “of special concern” in Canada. In 1998 and 1999, we marked 18 adult males wintering along the St. Lawrence River, Québec, with satellite transmitters to document their breeding, molting, and wintering distribution and phenology, and to describe timing and routes of their spring, molt, and fall migrations. Thirteen males moved inland from the St. Lawrence River to breed; the spring migration averaged 5.9 days, and birds arrived on breeding areas on average 9 May. All breeding areas were inland, on the north shore of the St. Lawrence River estuary and gulf. Breeding areas averaged 64.8 km from the St. Lawrence corridor. Males stayed on their respective breeding area a mean of 34.5 days, and left on average 11 June. Twelve males were tracked to their molting areas, one of which stayed on its wintering area until 5 June and flew directly to its molting area. Their molt migration averaged 18.6 days, and the mean arrival date on molting areas was 30 June. All molting areas were located north and averaged 986 km from breeding areas. Four males molted in Hudson Bay, four in Ungava Bay, two in northern Labrador, one on Baffin Island, and one inland, near the Québec–Labrador border. The mean length of stay on the molting areas was 105.3 days, and the mean date of departure from molting areas was 4 October. All goldeneyes for which the radio still functioned during fall migration returned to winter in the St. Lawrence River estuary, on average 6 November. Our results refute the idea that the main breeding area of the eastern North American population of Barrow's Goldeneyes is located in northern Québec and Labrador and rather indicate that it is in the boreal forest just north of the St. Lawrence River estuary and gulf. They also indicate that Barrow's Goldeneye males undertake a genuine molt migration, and highlight the importance of molting areas because birds stayed there approximately four months each year.

scholarly journals Despotic aggression in pre-moulting painted buntings

2020 ◽  
Vol 7 (2) ◽  
pp. 191510
Author(s):  
Vanya G. Rohwer ◽  
Sievert Rohwer ◽  
John C. Wingfield
Keyword(s):  
Breeding Season ◽  
Social Systems ◽  
Passerine Bird ◽  
Adult Males ◽  
Territorial Defence ◽  
Painted Bunting ◽  
High Aggression ◽  
Limited Food ◽  
Ideal Despotic ◽  
Territorial Systems

Aggression in territorial social systems is easy to interpret because the benefits of territorial defence mostly accrue to the territorial holder. However, in non-territorial systems, high aggression seems puzzling and raises intriguing evolutionary questions. We describe extreme rates of despotism between age classes in a passerine bird, the painted bunting ( Passerina ciris ), during the pre-moulting period. Aggressive encounters were not associated with aggressors gaining immediate access to resources. Instead, conspecifics, and even other species, were pursued as though being harassed; this aggression generated an ideal despotic habitat distribution such that densities of adult males were higher in high-quality sites. Aggression was not a by-product of elevated testosterone carried over from the breeding season but, rather, appeared associated with dehydroepiandrosterone, a hormone that changes rates of aggression in non-breeding birds without generating the detrimental effects of high testosterone titres that control aggression in the breeding season. This extraordinary pre-moult aggression seems puzzling because individual buntings do not hold defined territories during their moult. We speculate that this high aggression evolved as a means of regulating the number of conspecifics that moulted in what were historically small habitat patches with limited food for supporting the extremely rapid moults of painted buntings.

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