| Records |
| Author |
Keiper, R.; Houpt, K. |
| Title |
Reproduction in feral horses: an eight-year study |
Type |
Journal Article |
| Year |
1984 |
Publication |
American journal of veterinary research |
Abbreviated Journal |
Am J Vet Res |
| Volume |
45 |
Issue |
5 |
Pages |
991-995 |
| Keywords |
Abortion, Veterinary/epidemiology; Anestrus; Animal Population Groups/*physiology; Animals; Animals, Wild/*physiology; Birth Rate; Female; Fertility; Horse Diseases/epidemiology; Horses/*physiology; Lactation; Male; Maryland; Pregnancy; *Reproduction; Seasons; Sex Ratio; Virginia |
| Abstract |
The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and less than 1% in August and September. The mean foaling rate was 57.1 +/- 3.9% and the survival rate was 88.3 +/- 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares less than 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 +/- 2.4%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore , the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or greater than 10%/yr. There were 24 deaths and 8 dispersals from the study area. |
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Place of Publication |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0002-9645 |
ISBN |
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Medium |
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Expedition  |
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Conference |
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| Notes |
PMID:6732036 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
665 |
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| Author |
Cancedda, M. |
| Title |
[Social and behavioral organization of horses on the Giara (Sardinia): distribution and aggregation] |
Type |
Journal Article |
| Year |
1990 |
Publication |
Bollettino della Societa italiana di biologia sperimentale |
Abbreviated Journal |
Boll Soc Ital Biol Sper |
| Volume |
66 |
Issue |
11 |
Pages |
1089-1096 |
| Keywords |
Animals; *Animals, Wild/physiology/psychology; Environment; Female; *Horses/physiology/psychology; Italy; Male; Population Density; Sexual Behavior, Animal; *Social Behavior; Social Dominance; Water |
| Abstract |
In this paper some considerations on the environment of the 42 Kmq of the volcanic-basaltic Giara tableland are discussed. Conditioning by the environment and its effect on the distribution of a population of 712 horses is illustrated in view of their social and behavioural organization. |
| Address |
Istituto di Fisiologia Generale e Speciale, Universita di Sassari |
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Place of Publication |
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Editor |
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| Language |
Italian |
Summary Language |
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Original Title |
Introduzione all'organizzazione sociale e comportamentale dei cavallini sulla Giara (Sardegna): distribuzione ed aggregazione |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0037-8771 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:2095819 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
673 |
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| Author |
Kostova, T.; Carlsen, T.; Kercher, J. |
| Title |
Individual-based spatially-explicit model of an herbivore and its resource: the effect of habitat reduction and fragmentation |
Type |
Journal Article |
| Year |
2004 |
Publication |
Comptes Rendus Biologies |
Abbreviated Journal |
Compt. Rend. Biol. |
| Volume |
327 |
Issue |
3 |
Pages |
261-276 |
| Keywords |
complexity; population dynamics; self-organization; population waves; individual-based models |
| Abstract |
We present an individual-based, spatially-explicit model of the dynamics of a small mammal and its resource. The life histories of each individual animal are modeled separately. The individuals can have the status of residents or wanderers and belong to behaviorally differing groups of juveniles or adults and males or females. Their territory defending and monogamous behavior is taken into consideration. The resource, green vegetation, grows depending on seasonal climatic characteristics and is diminished due to the herbivore's grazing. Other specifics such as a varying personal energetic level due to feeding and starvation of the individuals, mating preferences, avoidance of competitors, dispersal of juveniles, as a result of site overgrazing, etc., are included in the model. We determined model parameters from real data for the species Microtus ochrogaster (prairie vole). The simulations are done for a case of an enclosed habitat without predators or other species competitors. The goal of the study is to find the relation between size of habitat and population persistence. The experiments with the model show the populations go extinct due to severe overgrazing, but that the length of population persistence depends on the area of the habitat as well as on the presence of fragmentation. Additionally, the total population size of the vole population obtained during the simulations exhibits yearly fluctuations as well as multi-yearly peaks of fluctuations. This dynamics is similar to the one observed in prairie vole field studies. To cite this article: T. Kostova et al., C. R. Biologies 327 (2004). |
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Conference |
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Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
801 |
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| Author |
Hirsch, B.T. |
| Title |
Costs and benefits of within-group spatial position: a feeding competition model |
Type |
Journal Article |
| Year |
2007 |
Publication |
The Quarterly review of biology |
Abbreviated Journal |
Q Rev Biol |
| Volume |
82 |
Issue |
1 |
Pages |
9-27 |
| Keywords |
Animals; Competitive Behavior/*physiology; Dominance-Subordination; Feeding Behavior/*physiology/*psychology; Population Dynamics; Predatory Behavior/*physiology |
| Abstract |
An animal's within-group spatial position has several important fitness consequences. Risk of predation, time spent engaging in antipredatory behavior and feeding competition can all vary with respect to spatial position. Previous research has found evidence that feeding rates are higher at the group edge in many species, but these studies have not represented the entire breadth of dietary diversity and ecological situations faced by many animals. In particular the presence of concentrated, defendable food patches can lead to increased feeding rates by dominants in the center of the group that are able to monopolize or defend these areas. To fully understand the tradeoffs of within-group spatial position in relation to a variety of factors, it is important to be able to predict where individuals should preferably position themselves in relation to feeding rates and food competition. A qualitative model is presented here to predict how food depletion time, abundance of food patches within a group, and the presence of prior knowledge of feeding sites affect the payoffs of different within-group spatial positions for dominant and subordinate animals. In general, when feeding on small abundant food items, individuals at the front edge of the group should have higher foraging success. When feeding on slowly depleted, rare food items, dominants will often have the highest feeding rates in the center of the group. Between these two extreme points of a continuum, an individual's optimal spatial position is predicted to be influenced by an additional combination of factors, such as group size, group spread, satiation rates, and the presence of producer-scrounger tactics. |
| Address |
Department of Anthropology, Stony Brook University Stony Brook, New York 11794, USA. BTHIRSCH@IC.SUNYSB.EDU |
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Thesis |
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Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0033-5770 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:17354992 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
803 |
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| Author |
De Stoppelaire, G.H.; Gillespie, T.W.; Brock, J.C.; Tobin, G.A. |
| Title |
Use of remote sensing techniques to determine the effects of grazing on vegetation cover and dune elevation at Assateague Island National Seashore: impact of horses |
Type |
Journal Article |
| Year |
2004 |
Publication |
Environmental Management |
Abbreviated Journal |
Environ Manage |
| Volume |
34 |
Issue |
5 |
Pages |
642-649 |
| Keywords |
Animals; Animals, Wild; Conservation of Natural Resources; Ecosystem; Environmental Monitoring; *Feeding Behavior; *Horses; Maryland; Plants/*growth & development; Population Dynamics; Silicon Dioxide; *Soil |
| Abstract |
The effects of grazing by feral horses on vegetation and dune topography at Assateague Island National Seashore were investigated using color-infrared imagery, lidar surveys, and field measurements. Five pairs of fenced and unfenced plots (300 m2) established in 1993 on sand flats and small dunes with similar elevation, topography, and vegetation cover were used for this study. Color-infrared imagery from 1998 and field measurements from 2001 indicated that there was a significant difference in vegetation cover between the fenced and unfenced plot-pairs over the study period. Fenced plots contained a higher percentage of vegetation cover that was dominated by American beachgrass (Ammophila breviligulata). Lidar surveys from 1997, 1999, and 2000 showed that there were significant differences in elevation and topography between fenced and unfenced plot-pairs. Fenced plots were, on average, 0.63 m higher than unfenced plots, whereas unfenced plots had generally decreased in elevation after establishment in 1993. Results demonstrate that feral horse grazing has had a significant impact on dune formation and has contributed to the erosion of dunes at Assateague Island. The findings suggest that unless the size of the feral horse population is reduced, grazing will continue to foster unnaturally high rates of dune erosion into the future. In order to maintain the natural processes that historically occurred on barrier islands, much larger fenced exclosures would be required to prevent horse grazing. |
| Address |
US Geological Survey, Center for Coastal and Watershed Studies, St. Petersburg, Florida 33701, USA. georgia.destoppelaire@my.FWC.com |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0364-152X |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:15633024 |
Approved |
no |
| Call Number |
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Serial |
1896 |
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| Author |
Feist, J.D.; McCullough, D.R. |
| Title |
Reproduction in feral horses |
Type |
Journal Article |
| Year |
1975 |
Publication |
Journal of Reproduction and Fertility. Supplement |
Abbreviated Journal |
J Reprod Fertil Suppl |
| Volume |
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Issue |
23 |
Pages |
13-18 |
| Keywords |
Age Factors; Animals; Female; Horses/*physiology; Leadership; Male; Maternal Behavior; Population; Reproduction; *Sexual Behavior, Animal; Social Dominance; Sucking Behavior |
| Abstract |
A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only. |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0449-3087 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:1060766 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
1964 |
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| Author |
Hrdy, S.B. |
| Title |
Male-male competition and infanticide among the langurs (Presbytis entellus) of Abu, Rajasthan |
Type |
Journal Article |
| Year |
1974 |
Publication |
Folia Primatologica; International Journal of Primatology |
Abbreviated Journal |
Folia Primatol (Basel) |
| Volume |
22 |
Issue |
1 |
Pages |
19-58 |
| Keywords |
Aggression; Animals; Animals, Newborn; Coitus; *Competitive Behavior; Estrus; Feeding Behavior; Female; *Haplorhini; Homing Behavior; Humans; India; Infanticide; Leadership; Male; Maternal Behavior; Population Density; Pregnancy; Rain; Seasons; Sex Factors; Sexual Behavior, Animal; Social Behavior; Temperature; Vocalization, Animal |
| Abstract |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0015-5713 |
ISBN |
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Medium |
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Conference |
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| Notes |
PMID:4215710 |
Approved |
no |
| Call Number |
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Serial |
2051 |
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| Author |
Dubois, F.; Giraldeau, L.-A. |
| Title |
The forager's dilemma: food sharing and food defense as risk-sensitive foraging options |
Type |
Journal Article |
| Year |
2003 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
| Volume |
162 |
Issue |
6 |
Pages |
768-779 |
| Keywords |
Animals; Competitive Behavior/*physiology; *Environment; Feeding Behavior/*physiology; *Game Theory; *Models, Biological; Population Density; Population Dynamics |
| Abstract |
Although many variants of the hawk-dove game predict the frequency at which group foraging animals should compete aggressively, none of them can explain why a large number of group foraging animals share food clumps without any overt aggression. One reason for this shortcoming is that hawk-dove games typically consider only a single contest, while most group foraging situations involve opponents that interact repeatedly over discovered food clumps. The present iterated hawk-dove game predicts that in situations that are analogous to a prisoner's dilemma, animals should share the resources without aggression, provided that the number of simultaneously available food clumps is sufficiently large and the number of competitors is relatively small. However, given that the expected gain of an aggressive animal is more variable than the gain expected by nonaggressive individuals, the predicted effect of the number of food items in a clump-clump richness-depends on whether only the mean or both the mean and variability associated with payoffs are considered. More precisely, the deterministic game predicts that aggression should increase with clump richness, whereas the stochastic risk-sensitive game predicts that the frequency of encounters resulting in aggression should peak at intermediate clump richnesses or decrease with increasing clump richness if animals show sensitivity to the variance or coefficient of variation, respectively. |
| Address |
Departement des Sciences Biologiques, Universite du Quebec a Montreal, Case postale 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. fdubois@u-bourgogne.fr |
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English |
Summary Language |
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Original Title |
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Series Issue |
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Edition |
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| ISSN |
0003-0147 |
ISBN |
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Conference |
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| Notes |
PMID:14737714 |
Approved |
no |
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Serial |
2132 |
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| Author |
Gauvin, S.; Giraldeau, L.-A. |
| Title |
Nutmeg mannikins ( Lonchura punctulata) reduce their feeding rates in response to simulated competition |
Type |
Journal Article |
| Year |
2004 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
| Volume |
139 |
Issue |
1 |
Pages |
150-156 |
| Keywords |
Animals; *Feeding Behavior; Population Density; *Social Behavior; *Songbirds |
| Abstract |
Group feeding animals experience a number of competitive foraging costs that may result in a lowered feeding rate. It is important to distinguish between reductions in feeding rates that are caused by reduced food availability and physical interactions among foragers from those caused by the mere presence of foraging companions that may be self-imposed in order to obtain some benefit of group membership. Starlings ( Sturnus vulgaris) reduce their feeding rates when in the company of simulated competitors located in an adjacent cage that cannot affect the food availability or interact with the forager. In the present study, we investigate whether the presence of simulated competitors in another species of passerine, nutmeg mannikins ( Lonchura punctulata), can result in self-imposed reductions in feeding rates. When feeding in the company of simulated competitors, mannikins spent more non-foraging time near them, fed more slowly, reduced travel times between patches, reduced their scanning time and pecked more slowly. These results provide evidence that simulated competitors induce a reduction in pecking rate: behavioural interference. These self-imposed responses to competitors may have resulted from attempts to remain close to the non-feeding companions. Such self-imposed reductions in feeding rates may be a widespread yet generally unrecognised foraging cost to group feeding individuals. |
| Address |
Department of Biology, Concordia University, Montreal, Quebec, Canada |
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English |
Summary Language |
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0029-8549 |
ISBN |
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| Notes |
PMID:14722748 |
Approved |
no |
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Serial |
2133 |
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| Author |
Ward, M.P.; Ramsay, B.H.; Gallo, K. |
| Title |
Rural cases of equine West Nile virus encephalomyelitis and the normalized difference vegetation index |
Type |
Journal Article |
| Year |
2005 |
Publication |
Vector Borne and Zoonotic Diseases (Larchmont, N.Y.) |
Abbreviated Journal |
Vector Borne Zoonotic Dis |
| Volume |
5 |
Issue |
2 |
Pages |
181-188 |
| Keywords |
Animals; Biomass; Cluster Analysis; Disease Outbreaks/veterinary; Ecology; *Geographic Information Systems; Horse Diseases/*epidemiology; Horses; Indiana/epidemiology; Plants; Population Surveillance; Rural Health; Seasons; Topography, Medical/*methods; West Nile Fever/epidemiology/*veterinary |
| Abstract |
Data from an outbreak (August to October, 2002) of West Nile virus (WNV) encephalomyelitis in a population of horses located in northern Indiana was scanned for clusters in time and space. One significant (p = 0.04) cluster of case premises was detected, occurring between September 4 and 10 in the south-west part of the study area (85.70 degrees N, 45.50 degrees W). It included 10 case premises (3.67 case premises expected) within a radius of 2264 m. Image data were acquired by the Advanced Very High Resolution Radiometer (AVHRR) sensor onboard a National Oceanic and Atmospheric Administration polar-orbiting satellite. The Normalized Difference Vegetation Index (NDVI) was calculated from visible and near-infrared data of daily observations, which were composited to produce a weekly-1km(2) resolution raster image product. During the epidemic, a significant (p < 0.01) decrease (0.025 per week) in estimated NDVI was observed at all case and control premise sites. The median estimated NDVI (0.659) for case premises within the cluster identified was significantly (p < 0.01) greater than the median estimated NDVI for other case (0.571) and control (0.596) premises during the same period. The difference in median estimated NDVI for case premises within this cluster, compared to cases not included in this cluster, was greatest (5.3% and 5.1%, respectively) at 1 and 5 weeks preceding occurrence of the cluster. The NDVI may be useful for identifying foci of WNV transmission. |
| Address |
Department of Veterinary Pathobiology, Purdue University School of Veterinary Medicine, West Lafayette, Indiana, USA. mward@cvm.tamu.edu |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1530-3667 |
ISBN |
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| Notes |
PMID:16011435 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2627 |
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