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Nowak BVR, Bowen WD, den Heyer CE, Lang SLC, Lidgard DC. Ontogeny of movement patterns in naïve grey seal pups inhabiting a complex continental shelf ecosystem. PLoS One 2023; 18:e0290707. [PMID: 37756252 PMCID: PMC10529606 DOI: 10.1371/journal.pone.0290707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 08/14/2023] [Indexed: 09/29/2023] Open
Abstract
Most vertebrate offspring must transition from the relative security of parental care (nutrition and protection) to independent foraging. Offspring face many challenges during this critical period, particularly in species where parental care ends at weaning, such as the grey seal (Halichoerus grypus). We studied the development of movement behaviour in naïve grey seal pups from their first trips to sea to about five months of age. Twenty-five (12 males and 13 females) newly-weaned pups were fitted with satellite-linked GPS tags on Sable Island, Nova Scotia, Canada in January 2016. The influence of fixed effects (pup size, sex, week) and the random effect of pup identity on trip characteristics were examined. Movement behaviour was analyzed using a move persistence mixed-effects model. Habitat use was highly variable among individuals and covered much of the geographic distribution of the population. Unlike older juveniles, subadults, and adults in this population, most naïve pups used multiple haulout sites to begin and end trips. There was little evidence of area-restricted search behaviour during trips, suggesting that naïve pups were using an opportunistic foraging tactic that may result in more variable foraging success than that of older, experienced animals. Naïve pups made longer trips with longer haulout durations between them than observed for older greys seals. Males and females differed in some trip characteristics, but sex effects were small over the first few months of life. Offspring size at weaning was not a useful predictor of trip characteristics. Move persistence of grey seal pups was initially high and then decreased over time as individuals gained experience. Both intrinsic and extrinsic factors were influential on the movements of grey seal pups. Greater body length at weaning, longer duration spent on shore after weaning, shallower water column depth, and farther distance from shore were all associated with lower move persistence. Female grey seal pups had lower move persistence than males. Overall, the movements of naïve grey seal pups during the first few months of life were characterized by extensive exploration, but move persistence decreased over time suggesting they may be using an exploration-refinement foraging tactic.
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Affiliation(s)
- Benia V. R. Nowak
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - W. Don Bowen
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Cornelia E. den Heyer
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Shelley L. C. Lang
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
- Northwest Atlantic Fisheries Centre, St. John’s, Newfoundland, Canada
| | - Damian C. Lidgard
- Biology Department, Life Science Centre Dalhousie University, Halifax, Nova Scotia, Canada
- Population Ecology Division, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Individual Quality Drives Life History Variation in a Long-Lived Marine Predator. Am Nat 2023; 202:351-367. [PMID: 37606942 DOI: 10.1086/725451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
AbstractIndividual quality and environmental conditions may mask or interact with energetic trade-offs in life history evolution. Deconstructing these sources of variation is especially difficult in long-lived species that are rarely observed on timescales long enough to disentangle these effects. Here, we investigated relative support for variation in female quality and costs of reproduction as factors shaping differences in life history trajectories using a 32-year dataset of repeated reproductive measurements from 273 marked, known-age female gray seals (Halichoerus grypus). We defined individual reproductive investment using two traits, reproductive frequency (a female's probability of breeding) and provisioning performance (offspring weaning mass). Fitted hierarchical Bayesian models identified individual investment relative to conspecifics (over a female's entire life and in three age classes) and subsequently estimated how these investment metrics and the Atlantic Multidecadal Oscillation are associated with longevity. Individual differences (i.e., quality) contributed a large portion of the variance in reproductive traits. Females that consistently invest well in their offspring relative to other females survive longer. The best-supported model estimated survival as a function of age class-specific provisioning performance, where late-life performance was particularly variable and had the greatest impact on survival, possibly indicating individual variation in senescence. There was no evidence to support a trade-off in reproductive performance and survival at the individual level. Overall, these results suggest that in gray seals, individual quality is a stronger driver in life history variation than individual strategies resulting from energetic trade-offs.
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Patterns and causes of breeding dispersal in a declining population of Canada jays, Perisoreus canadensis, over 55 years. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fuirst M, Strickland D, Norris DR. Breeding dispersal in a resident boreal passerine can lead to short‐ and long‐term fitness benefits. Ecosphere 2021. [DOI: 10.1002/ecs2.3747] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Matthew Fuirst
- Department of Integrative Biology University of Guelph Guelph Ontario Canada N1G 2W1
| | | | - D. Ryan Norris
- Department of Integrative Biology University of Guelph Guelph Ontario Canada N1G 2W1
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Bowen WD, den Heyer CE, Lang SLC, Lidgard D, Iverson SJ. Exploring causal components of plasticity in grey seal birthdates: Effects of intrinsic traits, demography, and climate. Ecol Evol 2020; 10:11507-11522. [PMID: 33144980 PMCID: PMC7593198 DOI: 10.1002/ece3.6787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/22/2020] [Accepted: 07/28/2020] [Indexed: 11/08/2022] Open
Abstract
Change in breeding phenology is often a response to environmental forcing, but less is known of the mechanism underlying such changes and their fitness consequences. Here, we report on changes in the breeding phenology from a 27-year longitudinal study (1991-2017) of individually marked, known-aged grey seals (Halichoerus grypus) on Sable Island, Nova Scotia, Canada. We used generalized linear mixed models and a 3-step process to develop a model that includes interactions between intrinsic and extrinsic covariates and to test hypotheses about the influence of fixed factors (maternal age, parity, previous reproductive success, pup sex, colony density, Atlantic Multidecal Oscillation (AMO), North Atlantic Oscillation (NAO), and Sea Surface Temperature) and a random factor (female identity) on parturition dates. We also examined the consequences of the shift in birthdates on maternal energy allocation in offspring as measured by pup weaning mass. Birthdates were known for 2,768 pups of 660 known-age females. For 494 females with ≥2 parturition dates, repeatability as measured by the intraclass correlation was high (mean = 0.66). 87% of the variation in birthdates was explained by a mixed-effects model that included intrinsic and extrinsic fixed effects. Most of the explained variation was associated with the random effect of female identity. Parity was the most important intrinsic fixed effect, with inexperienced mothers giving birth later in the season than multiparous females. Over almost 3 decades, mean birthdates advanced by 15 days. The mixed model with intrinsic effects and population size, the detrended AMO from the previous year and mean NAO in the previous 3 years explained 80% of the variation with 21% of variation from the fixed effects. Both primiparous and multiparous individuals responded to the climate forcing, and there was strong evidence for heterogeneity in the response. Nevertheless, the shift in birthdates did not impact pup weaning mass.
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Affiliation(s)
- William Don Bowen
- Population Ecology DivisionBedford Institute of OceanographyDartmouthNSCanada
- Department of BiologyDalhousie UniversityHalifaxNSCanada
| | | | - Shelley L. C. Lang
- Population Ecology DivisionBedford Institute of OceanographyDartmouthNSCanada
- Department of BiologyDalhousie UniversityHalifaxNSCanada
| | - Damian Lidgard
- Department of BiologyDalhousie UniversityHalifaxNSCanada
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Badger JJ, Bowen WD, den Heyer CE, Breed GA. Variation in individual reproductive performance amplified with population size in a long‐lived carnivore. Ecology 2020; 101:e03024. [DOI: 10.1002/ecy.3024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/12/2019] [Accepted: 01/22/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Janelle J. Badger
- Department of Biolog y and Wildlife University of Alaska Fairbanks Fairbanks Alaska756100 USA
| | - W. Don Bowen
- Department of Fisheries and Oceans Canada Bedford Institute of Oceanography 1 Challenger Dr Dartmouth Nova Scotia Canada
| | - Cornelia E. den Heyer
- Department of Fisheries and Oceans Canada Bedford Institute of Oceanography 1 Challenger Dr Dartmouth Nova Scotia Canada
| | - Greg A. Breed
- Department of Biolog y and Wildlife University of Alaska Fairbanks Fairbanks Alaska756100 USA
- Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska757000 USA
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Shuert CR, Pomeroy PP, Twiss SD. Coping styles in capital breeders modulate behavioural trade-offs in time allocation: assessing fine-scale activity budgets in lactating grey seals (Halichoerus grypus) using accelerometry and heart rate variability. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2783-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
Balancing time allocation among competing behaviours is an essential part of energy management for all animals. However, trade-offs in time allocation may vary according to the sex of the individual, their age, and even underlying physiology. During reproduction, higher energetic demands and constrained internal resources place greater demand on optimizing these trade-offs insofar that small adjustments in time-activity may lead to substantial effects on an individual’s limited energy budget. The most extreme case is found in animals that undergo capital breeding, where individuals fast for the duration of each reproductive episode. We investigated potential underlying drivers of time-activity and describe aspects of trade-offs in time-activity in a wild, capital breeding pinniped, the grey seal Halichoerus grypus, during the lactation period. For the first time, we were able to access full 24-h activity budgets across the core duration of lactation as well as characterize how aspects of stress-coping styles influence time allocation through the use of animal-borne accelerometers and heart rate monitors in situ. We found that there was a distinct trade-off in time activity between time spent Resting and Alert (vigilance). This trade-off varied with the pup’s development, date, and maternal stress-coping style as indicated by a measure of heart rate variability, rMSSD. In contrast, time spent Presenting/Nursing did not vary across the duration of lactation given the variables tested. We suggest that while mothers balance time spent conserving resources (Resting) against time expending energy (Alert), they are also influenced by the inherent physiological drivers of stress-coping styles.
Significance statement
How animals apportion their time among different behaviours is key to their success. These trade-offs should be finely balanced to avoid unnecessary energy expenditure. Here, we examine how grey seal mothers balance their activity patterns during the short, but energetically demanding, period of pup-rearing. Animal-borne accelerometers provided a uniquely detailed and continuous record of activity during pup-rearing for 38 mothers. We also used heart rate monitors to provide measures of each individual’s stress-coping style. We found that mothers balance time Resting against remaining Alert while time Presenting/Nursing was largely independent of all factors measured. Stress-coping styles were found to drive the balancing and variation of all behaviours. This novel indication that differences in personality-like traits may drive whole activity budgets should be considered when assessing trade-offs in time allocation across a much wider variety of species.
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Causes and consequences of avian within-season dispersal decisions in a dynamic grassland environment. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Seabirds fighting for land: phenotypic consequences of breeding area constraints at a small remote archipelago. Sci Rep 2018; 8:665. [PMID: 29330422 PMCID: PMC5766501 DOI: 10.1038/s41598-017-18808-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 12/16/2017] [Indexed: 11/08/2022] Open
Abstract
Identifying associations between phenotypes and environmental parameters is crucial for understanding how natural selection acts at the individual level. In this context, genetically isolated populations can be useful models for identifying the forces selecting fitness-related traits. Here, we use a comprehensive dataset on a genetically and ecologically isolated population of the strictly marine bird, the brown booby Sula leucogaster, at the tropical and remote Saint Peter and Saint Paul Archipelago, mid-Atlantic Ocean, in order to detect phenotypic adjustments from interindividual differences in diet, foraging behaviour, and nest quality. For this, we took biometrics of all individuals of the colony breeding in 2014 and 2015 and tested their associations with nest quality, diet parameters, and foraging behaviour. While body size was not related to the foraging parameters, the body size of the females (responsible for nest acquisition and defence) was significantly associated with the nest quality, as larger females occupied high-quality nests. Our findings suggest that the small breeding area, rather than prey availability, is a limiting factor, emphasizing the role of on-land features in shaping phenotypic characteristics and fitness in land-dependent marine vertebrates.
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