Territory Size and Population Density in Relation to Food Supply in the Nuthatch Sitta europaea (Aves)

10.2307/4464 ◽  
1983 ◽  
Vol 52 (3) ◽  
pp. 927 ◽  
Author(s):  
Bodil Enoksson ◽  
Sven G. Nilsson
Keyword(s):  
Population Density ◽  
Food Supply ◽  
Territory Size ◽  
Sitta Europaea

Food of Nuthatch Sitta europaea Young in a Primeval Forest: Effects of Varying Food Supply and Age of Nestlings

2019 ◽  
Vol 54 (1) ◽  
pp. 85 ◽  
Author(s):  
Tomasz Wesołowski ◽  
Patryk Rowiński ◽  
Grzegorz Neubauer
Keyword(s):  
Food Supply ◽  
Primeval Forest ◽  
Sitta Europaea

Social organization, spatial distribution, and population density of wolves in relation to moose density

1985 ◽  
Vol 63 (5) ◽  
pp. 1068-1077 ◽  
Author(s):  
François Messier
Keyword(s):  
Spatial Distribution ◽  
Mortality Rate ◽  
Population Density ◽  
Social Organization ◽  
Prey Density ◽  
Territory Size ◽  
Wolf Population ◽  
Pack Size ◽  
Behavioral Attributes ◽  
Density Threshold

This 4-year study compared population density and related behavioral attributes of wolves (14 packs) at two different moose densities: 0.23 (LP, low prey density), and 0.37 (HP, high prey density) moose∙km−2. Wolf densities in January averaged 0.8 and 1.4 animals∙100 km−2, packs consisted of 3.7 and 5.7 individuals, year-long territory sizes were 255 and 390 km2, and interstices between territories represented 30 and [Formula: see text] of available area, for the LP and HP areas, respectively. Territory size increased significantly with pack size. The LP wolf population suffered from a higher mortality rate owing to a higher occurrence of deaths from malnutrition and intraspecific strife, and from a lower success in producing pups (61% of the possible occasions, compared with 93% in HP). When no other ungulate species is present, a density of 0.2 moose∙km−2 would approximate the density threshold below which a pack could not subsist and (or) reproduce successfully. The study reveals that naturally regulated moose–wolf systems may stabilize at low prey and low predator densities.

Territory Size as a Predictor of the Upper Limit to Population Density of Juvenile Salmonids in Streams

1990 ◽  
Vol 47 (9) ◽  
pp. 1724-1737 ◽  
Author(s):  
James W. A. Grant ◽  
Donald L. Kramer
Keyword(s):  
Population Density ◽  
Experimental Studies ◽  
Strong Support ◽  
Fork Length ◽  
Maximum Density ◽  
Territory Size ◽  
Published Data ◽  
Density Dependent ◽  
Size Limits ◽  
Density Regression

We examined the old, but untested hypothesis that territory size limits the maximum population density of salmonids in streams. We used published data to derive an interspecific regression of territory size (m2) on fork length (cm) (log10 territory size = 2.61 log10 length—2.83, r2 = 0.87, n = 23). Growth and mortality trajectories of salmonid cohorts from eight experimental studies were compared to the maximum-density regression, the inverse of the territory–size regression. In shallow habitats, such as riffles and raceways, the cohort trajectories followed the maximum density regression quite closely and were consistent with the territory–size hypothesis. In addition, natural densities in eight other studies did not exceed the predicted maximum density and tended to fail within the 95% C.L. of the maximum-density regression. Data from shallow habitats, therefore, provide strong support for the territory–size hypothesis. A linear logistic response model showed that the probability of observing density-dependent growth, mortality, or emigration increased significantly with increasing values of an index of habitat saturation, developed from the territory–size regression. Our results suggest that the territory–size regression has practical value for predicting the maximum densities of stream-dwelling salmonids in shallow habitats and the occurrence of density-dependent population responses.

scholarly journals The effect of visual isolation on territory size and population density of juvenile rainbow trout (Oncorhynchus mykiss)

2002 ◽  
Vol 59 (2) ◽  
pp. 303-309 ◽  
Author(s):  
I Imre ◽  
J WA Grant ◽  
E R Keeley
Keyword(s):  
Rainbow Trout ◽  
Population Density ◽  
Oncorhynchus Mykiss ◽  
Experimental Tests ◽  
Territory Size ◽  
Control Treatment ◽  
Stream Channels ◽  
Juvenile Salmonids ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Experimental Treatments

Visibility is thought to affect the territory size of visually oriented animals but there have been few experimental tests of the hypothesis. We re-examined the relationship between visibility and territory size in juvenile salmonids to test the hypothesis that increasing habitat heterogeneity results in a reduction in territory size and consequently in higher population densities. Equal densities of young-of-the-year rainbow trout (Oncorhynchus mykiss) were stocked in two experimental treatments with low visibility and a control treatment with high visibility. Visibility was decreased by placing large stones or plywood dividers onto the substrate of experimental stream channels. As predicted, the size of individual territories decreased with decreasing visibility of the habitat. However, the treatments did not differ significantly in population density or growth rate of the fish. While this study confirms the inverse relationship between habitat visibility and territory size, the decrease in territory size did not produce an increase in population density of juvenile salmonids.

scholarly journals Assessing the extent of occurrence, area of occupancy, territory size, and population size of marsh tapaculo (Scytalopus iraiensis)

2013 ◽  
Vol 36 (1) ◽  
pp. 47-57
Author(s):  
L. Klemann Jr. ◽  
◽  
J. S. Vieira ◽  
Keyword(s):  
Population Density ◽  
Population Size ◽  
Territory Size ◽  
Ecological Zones ◽  
Flood Plains ◽  
Area Of Occupancy ◽  
New Information ◽  
The Family ◽  
Rivers And Streams ◽  
Occurrence Records

First described in 1998, the marsh tapaculo (Scytalopus iraiensis) is an endangered bird of the family Rhinocryptidae. It is endemic to Brazil and is restricted to the wet flood plains of rivers and streams. Due to its cryptic habits and environments of occurrence, information available on its biology, natural history and distribution is scarce. We compiled occurrence records (99 records), delimited the extent of occurrences (296,584 km2), calculated the area of occupancy (84 km2), estimated territory size (5,313 ± 1,201 m2 per pair), population density (3.76 ± 0.85 individuals per hectare), and population size (31,584 ± 7,140 mature individuals) of marsh tapaculo. The species was recorded in marshes associated to four types of vegetation and in four ecological zones. This new information is extremely important to support revaluation of the species’ threat category and to enhance knowledge about this endemic and little known bird from Brazil.

Assessment of permanence and stability in the territories of Kirk's dikdik (Rhynchotragus kirki) in Tanzania

1990 ◽  
Vol 6 (2) ◽  
pp. 153-162 ◽  
Author(s):  
Felix O. Amubode ◽  
John I. Boshe
Keyword(s):  
Population Density ◽  
National Park ◽  
Canopy Cover ◽  
Pair Bond ◽  
Spatial Distance ◽  
Territory Size ◽  
Suitable Habitat ◽  
Shrub Canopy ◽  
Dry Seasons ◽  
Arusha National Park

ABSTRACTThe permanence and stability of 20 territories of the dikdik Rhynchotragus kirki, were studied at Arusha National Park Tanzania. Response criteria included the structure, size and vegetation attributes of territories, density of dikdik, and spatial distances between neighbouring territories. Fourteen of the territories studied were spatially fixed and stable while six were unstable. Two of the unstable territories were completely abandoned. Mean territory size was 0.11 and 0.13 ha during the rainy and dry seasons, respectively. 14.2% of circular territories and 42.9% of elliptical and kidney-shaped territories were stable. The figure of 55 dikdik km−2 sighted during morning censuses was lower than that for evening censuses by 13.5%. Spatial distance between territories ranged from 4.5 m to 100 m, an indication that population density might be a function of the size of suitable habitat. Although shrub canopy cover within stable territories decreased by 44.6% between 1982 and 1987, and some territories were realigned with changes in rainfall pattern, pair-bond was maintained by dikdik in 70% of the territories studied.

Feeding Correlates of Breeding and Social Organization in Two Galápagos Finches

The Auk ◽  
1984 ◽  
Vol 101 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Dolph Schluter
Keyword(s):  
Functional Response ◽  
Food Supply ◽  
Feeding Rate ◽  
Territory Size ◽  
Behavioral Differences ◽  
Nonbreeding Season ◽  
Seed Supply ◽  
Breeding Territory ◽  
Invertebrate Abundance ◽  
Arthropod Abundance

Abstract Several aspects of breeding and social behavior in two Galápagos finches are related to food supply. Geospiza fuliginosa is largely granivorous, and G. difficilis is largely insectivorous. Measurements show that breeding of both species occurred when arthropod abundance was high. Breeding stopped when arthropod abundance was declining but before it was low. Breeding-territory size in G. difficilis varied inversely with food supply. Territory size in G. fuliginosa was similar across sites and was not correlated with food supply. This difference between species may be attributed to differences in the effects of invertebrate and seed resources on the functional response of consumers: feeding rate of G. difficilis on invertebrates increased linearly with their supply, whereas feeding rate of G. fuliginosa on seeds was essentially independent of seed abundance. In the nonbreeding season, the granivore G. fuliginosa moved in flocks, whereas G. difficilis was more stationary and solitary. Data indicate that seed supply was temporally more variable than invertebrate abundance, and this helps account for dry-season behavioral differences between the species. Functional response and/or renewability of seeds and invertebrates may also have influenced behavior at that time.

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