The behavior of adult gray seals (Halichoerus grypus) in the early stages of the breeding season

1969 ◽  
Vol 47 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Austin W. Cameron
Keyword(s):  
Nova Scotia ◽  
Breeding Season ◽  
Mass Movement ◽  
Territorial Behavior ◽  
Halichoerus Grypus ◽  
Breeding Area ◽  
Early Stages ◽  
Gray Seals

A 4-week period, December 18, 1967, to January 16, 1968, was spent studying a colony of gray seals on the Basque Islands, Nova Scotia. Before hauling out on the breeding islands, the seals congregate on exposed reefs nearby, where they remain for several weeks. Once invasion of the breeding area begins there is a mass movement and the entire herd beaches within the space of a week. The first seal observed to haul out was a cow which whelped within 24 hours. The bulls take up stations almost immediately whereas the cows wander aimlessly over the breeding area until they have whelped. The spot at which the pup is born seems to determine the cow's station. For several days after the pup is born, the cow remains with it constantly; thereafter she goes to sea at regular intervals. For the first week to 10 days after beaching, the bulls exhibit no territorial behavior and it is possible the boundaries are not established until later. The resident bulls appeared to ignore each other and no fighting was observed.

Diving behaviour during the breeding season in the terrestrially breeding male grey seal: implications for alternative mating tactics

2003 ◽  
Vol 81 (6) ◽  
pp. 1025-1033 ◽  
Author(s):  
Damian C Lidgard ◽  
Daryl J Boness ◽  
W Don Bowen ◽  
Jim I McMillan
Keyword(s):  
Nova Scotia ◽  
Reproductive Success ◽  
Breeding Season ◽  
Foraging Behaviour ◽  
Diving Behaviour ◽  
Halichoerus Grypus ◽  
Phenotypic Traits ◽  
Alternative Mating Tactics ◽  
Grey Seal ◽  
Mating Tactics

We examined the diving behaviour of breeding male grey seals (Halichoerus grypus) at Sable Island, Nova Scotia, from 1997 to 2001. The proportion of time spent at sea varied between 0 and 78% (N = 30). Males engaged in deep (43.4 ± 3.3 m (mean ± SE), N = 27) diving, and these dives were clustered into bouts, which mostly occurred during long trips (62.2 ± 14.7 h). We suggest that males spent time foraging during deep dives. Shallow diving (5.9 ± 0.1 m, N = 27) accounted for 40.8% of dives, which were also clustered into bouts that mostly occurred during short trips (2.1 ± 0.37 h). We suggest that shallow diving comprised a suite of behaviours, but included little foraging behaviour. Phenotypic traits had little influence on diving behaviour. Further work is required to understand the extent to which foraging behaviour enhances reproductive success, and whether shallow diving is a component of the mating tactics of male grey seals at Sable Island.

scholarly journals Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals (Halichoerus grypus) at breeding colonies in Nova Scotia, Canada

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4467 ◽  
Author(s):  
Lauren Arona ◽  
Julian Dale ◽  
Susan G. Heaslip ◽  
Michael O. Hammill ◽  
David W. Johnston
Keyword(s):  
Image Analysis ◽  
Nova Scotia ◽  
Acoustic Properties ◽  
Matched Pair ◽  
Short Term ◽  
Gray Seal ◽  
Aircraft Systems ◽  
Sequential Image ◽  
Young Of The Year ◽  
Gray Seals

The use of small unoccupied aircraft systems (UAS) for ecological studies and wildlife population assessments is increasing. These methods can provide significant benefits in terms of costs and reductions in human risk, but little is known if UAS-based approaches cause disturbance of animals during operations. To address this knowledge gap, we conducted a series of UAS flights at gray seal breeding colonies on Hay and Saddle Islands in Nova Scotia, Canada. Using a small fixed-wing UAS, we assessed both immediate and short-term effects of surveys using sequential image analysis and between-flight seal counts in ten, 50 m2 random quadrats at each colony. Counts of adult gray seals and young-of-the-year animals between first and second flights revealed no changes in abundance in quadrats (matched pair t-test p > 0.69) and slopes approaching 1 for linear regression comparisons (r2 > 0.80). Sequential image analysis revealed no changes in orientation or posture of imaged animals. We also assessed the acoustic properties of the small UAS in relation to low ambient noise conditions using sound equivalent level (Leq) measurements with a calibrated U-MIK 1 and a 1/3 octave band soundscape approach. The results of Leq measurements indicate that small fixed-wing UAS are quiet, with most energy above 160 Hz, and that levels across 1/3 octave bands do not greatly exceed ambient acoustic measurements in a quiet field during operations at standard survey altitudes. As such, this platform is unlikely to acoustically disturb gray seals at breeding colonies during population surveys. The results of the present study indicate that the effects of small fixed-wing UAS on gray seals at breeding colonies are negligible, and that fixed-wing UAS-based approaches should be considered amongst best practices for assessing gray seal colonies.

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

Maternal behaviour and energy investment by grey seals (Halichoerus grypus) breeding on land-fast ice

1996 ◽  
Vol 74 (8) ◽  
pp. 1531-1541 ◽  
Author(s):  
Martha A. Haller ◽  
Kit M. Kovacs ◽  
Mike O. Hammill
Keyword(s):  
Mass Transfer ◽  
Mass Loss ◽  
Breeding Season ◽  
Breeding Habitat ◽  
Halichoerus Grypus ◽  
Maternal Behaviour ◽  
Similar Amount ◽  
Lactation Period ◽  
Energy Investment ◽  
Fast Ice

The grey seal (Halichoerus grypus) is a sexually dimorphic polygynous phocid that breeds in a synchronous fashion, within populations, on both sides of the North Atlantic Ocean. This study was designed to examine factors that may influence maternal behaviour and energy investment of females breeding on land-fast ice. The study was conducted on the ice around Amet Island, Nova Scotia, during the breeding seasons of 1992, 1993, and 1994. Scan sampling and ad libitum observation techniques were used to record behaviour. Mass transfer from mothers to pups was determined using serial mass records for pairs. Rate of pup mass gain was 2.5 ± 0.6 kg/day and pup mass at weaning 50.0 ± 7.3 kg. The duration of lactation was 15.2 ± 1.6 days. Maternal mass at parturition was 210.6 ± 23.8 kg and female mass loss during the lactation period was 75.0 ± 16.0 kg. This mass loss represented 35.7 ± 6.1% of their parturition mass. Efficiency of mass transfer was 0.52 ± 0.12. Breeding habitat influenced maternal behaviour. Compared with land-breeding grey seals, ice-breeding females had an intensified nursing period, during which females transferred a similar amount of energy to their pups over a shorter time frame. Additionally, females on land-fast ice gave birth more synchronously than is the case in land-breeding colonies. Date of parturition within the breeding season had some influence on female behaviour; females giving birth late in the season were more active than females breeding earlier. The behaviour of males may play a role in determining the optimum time for birthing. Adult males spent more time engaged in agonistic behaviours late in the breeding season and the resultant disruption of adjacent females may serve as a selective force maintaining birthing synchrony. These influences also apply in land-breeding situations and are not likely to contribute to the contraction of the nursing period and the more synchronous breeding observed among females on ice. The more condensed lactation and birthing periods are likely a response to the higher risk of premature separation on the ice.

Nasal heat and water exchange in gray seals

1987 ◽  
Vol 253 (6) ◽  
pp. R883-R889 ◽  
Author(s):  
L. P. Folkow ◽  
A. S. Blix
Keyword(s):  
Water Exchange ◽  
Ambient Air ◽  
Minute Volume ◽  
Halichoerus Grypus ◽  
Evaporative Water ◽  
Air Temperatures ◽  
Respiratory Heat Loss ◽  
Average Maximum ◽  
Lower Critical Temperature ◽  
Gray Seals

Metabolic rate (MR), expired air temperature (Tex), respiratory frequency (f), respiratory minute volume (V), and skin (Ts) and body (Tb) temperatures were recorded in three gray seals (Halichoerus grypus) at ambient air temperatures (Ta) between -40 and +20 degrees C. At Ta within the thermoneutral zone, MR averaged 3.7 W.kg-0.75, while mean V was 0.26 1.min-1.kg-0.75. At Ta below -11 degrees C [apparent lower critical temperature (Tlc)], both MR and V increased linearly with decreasing Ta. Average maximum MR (9.6 W.kg-0.75) and V (0.57 1.min-1.kg-0.75) were both recorded at Ta of -40 degrees C. Tex decreased with decreasing Ta to an average minimum value of 8 degrees C at Ta of -30 degrees C. The highest Tex recorded was 32 degrees C at Ta of +20 degrees C. At Ta of -20 degrees C, both total respiratory heat loss, with one exception, and respiratory evaporative water loss reached their lowest values. At this Ta, 66% of the heat and 80% of the water added to the inspired air were regained on expiration. We suggest that nasal heat exchange may be of considerable importance for thermal and water balance in many pinnipeds.

Seasonal variability and individual consistency in gray seal (Halichoerus grypus) isotopic niches

2019 ◽  
Vol 97 (11) ◽  
pp. 1071-1077
Author(s):  
K.M. Hernandez ◽  
A.L. Bogomolni ◽  
J.H. Moxley ◽  
G.T. Waring ◽  
R.A. DiGiovanni ◽  
...  
Keyword(s):  
United States ◽  
Seasonal Variability ◽  
Foraging Ecology ◽  
Population Level ◽  
The United States ◽  
Halichoerus Grypus ◽  
Dietary Specialization ◽  
Gray Seal ◽  
Individual Consistency ◽  
Gray Seals

Although it is often assumed that individuals in generalist populations are equivalent, recent research indicates that individual dietary specialization can be common in marine predators. Gray seals (Halichoerus grypus (Fabricius, 1791)) were considered locally extinct in United States waters by 1958 but have since recolonized the region. Although considered generalists, less is known about gray seal foraging ecology in the United States. To address this, we used carbon and nitrogen stable isotope analyses to investigate the foraging niches of adult gray seals in Massachusetts, USA. We examined skin, fur, and blood components to investigate seasonal variability and individual consistency in foraging niches, and serially sampled vibrissae to quantify the degree of individual foraging specialization in this population. Our results suggest that seals shift from coastal foraging habitats before molt to offshore habitats after molt, with a coincident shift from higher to lower trophic-level prey. Adult gray seals also exhibited individual consistency in foraging niches independent of population-level shifts and reflect a generalist population composed of individual foraging specialists. These findings serve as a baseline for subsequent research on gray seals in United States waters that could help to determine the mechanisms which promote individual specialization in this population.

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