Sentences with phrase «predation rates in»

Not exact matches

The difference in the seals» survival rates could be a result of an increase in shark predation within the reserve.

Though we often think of mammals in the order Carnivora as predators, many of these species are themselves subject to high rates of predation and, as such, have evolved a suite of antipredator defenses that tend to sort them into two quite different categories.

«This is the first illustration that the spiders could also use the chemical cues to try to decrease the predation rate and also increase the attraction of prey,» says I - Min Tso of Tunghai University in Taiwan, who wasn't involved in the study.

He found higher rates of nest predation in small woodlots near human communities because these areas had higher populations of raccoons (Procyon lotor) and squirrels (Sciurus spp.) and few, if any, large predators, such as cougars and bobcats (Lynx rufus).

On landscapes with both open and closed habitat structure, they may use a combined strategy of hiding in forest cover to lower predator encounter rates and seeking open terrain, such as grasslands, where predation risk may be reduced.

The ASN Presidential Award for the paper that best fulfills the goals of the ASN in the American Naturalist during 2015 is «The Evolution of Foraging Rate across Local and Geographic Gradients in Predation Risk and Competition» by Mark C. Urban and Jonathan L. Richardson

Higher metabolic and survival costs induced by predation risk were only partially offset by changes in consumption rates and assimilation efficiencies and the magnitude of non-consumptive effects varied as a function of temperature.

A related concept, the mesopredator release hypothesis, predicts that the removal of apex predators leads to the irruption of mesopredators with concomitant declines in the abundances of their prey owing to elevated rates of predation by mesopredators [10].

In addition, overlap in use of nest sites with coexisting species may increase nest predation rates [21In addition, overlap in use of nest sites with coexisting species may increase nest predation rates [21in use of nest sites with coexisting species may increase nest predation rates [21].

Hunters and non-hunters: skewed predation rate by domestic cats in a rural village.

At a larger scale, this method would more accurately assess the seasonal variation in predation rates, individual hunting behavior throughout the year and the actual impact of cat predation on prey populations (Tschanz et al., 2011).

Marra and his colleagues extrapolated findings from 21 studies in the U.S. and Europe to come up with an estimate of 30 million to 80 million «unowned» cats and 84 million «owned» cats in the U.S., their kill rates, and other factors leading to bird predation.

``... the ecological and conservation significance of these kill tallies is difficult to contextualise, because (1) there are no reliable estimates of the total population of birds in Australia; (2) predation may fall disproportionately on some bird species; (3) some bird species may be able to sustain high mortality rates and maintain viable populations but others may not; and (4) as demonstrated here, there is substantial spatial variation in the numbers and proportion of birds killed across Australia.»

In other words, no difference between predation rates predicted by actual hunting observation and those predicted by way of prey returned home.

Indeed, such a question will invariably overestimate the number of «outdoor cats» — which in turn overestimates predation rates.

In fact, David Barratt found this kind of guesswork to overestimate predation rates.

«In Illinois, George (1974) found that only about half of animals killed by cats were provided to their owners, and in upstate New York, Kays and DeWan (2004) found that observed cat predation rates were 3.3 times higher than predation rates measured through prey returns to ownerIn Illinois, George (1974) found that only about half of animals killed by cats were provided to their owners, and in upstate New York, Kays and DeWan (2004) found that observed cat predation rates were 3.3 times higher than predation rates measured through prey returns to ownerin upstate New York, Kays and DeWan (2004) found that observed cat predation rates were 3.3 times higher than predation rates measured through prey returns to owners.

The two inflated figures described in (1) and (2) are multiplied together, further inflating estimated predation rates.

In it, she touches on all the usual talking points (e.g., cats are non-native, exaggerated predation rates, etc.), and portrays her trapping as a civic duty — done in the best interest not only of the community, but also of the catIn it, she touches on all the usual talking points (e.g., cats are non-native, exaggerated predation rates, etc.), and portrays her trapping as a civic duty — done in the best interest not only of the community, but also of the catin the best interest not only of the community, but also of the cats.

So, whereas Dauphiné and Cooper (and others) suggest increasing such estimates by factors of two and three («predation rates measured through prey returns may represent one half to less than one third of what pet cats actually kill...» [14]-RRB-, they should, in fact, be reducing them by half.

So, even setting aside the complexities of source - sink dynamics, these inflated predation rates, combined with the fact that «the estimates of breeding density presented in this manuscript should be regarded as minima,» [3] raise serious doubts about whether the site is in fact a habitat sink (or, if so, to what extent).

Summarizing a recent study of gray catbird fledglings in the Washington, DC area, the SMBC claims that cats were responsible for «alarmingly high rates of nest predation and fledging [sic] mortality.»

In their recently released book, The American Bird Conservancy Guide to Bird Conservation, ABC changes tack a bit — using what the authors call «conservative» estimates of the outdoor cat population and annual predation rates, for example, to arrive at their figure of «532 million birds killed annually by outdoor cats.»

Studies were only included if: (1) they clearly reported cat ranging behaviour (that is, a description of whether cats were owned or un-owned and whether they were outdoor cats or indoor - outdoor cats), and (2) the group of cats investigated fit exclusively into one of the two groups we defined above (that is, we excluded studies that lumped owned and un-owned cats in a single predation rate estimate).

Seasonal differences in predation rates were quantified using data from those cats from single - cat households studied for ≥ 4 seasons; where an individual had been studied in the same season for two years, predation rates for that season were averaged.

Our finding that un-owned cat population size and predation rate explained the greatest variation in mortality estimates reflects the current lack of knowledge about un-owned cats.

Data on predation rates by pet cats in Canada would also be very helpful.»

where npc is the number of owned cats in the contiguous United States, pod is the proportion of owned cats granted outdoor access, pph is the proportion of outdoor owned cats that hunt wildlife, ppr is the annual predation rate by owned cats, cor is a correction factor to account for owned cats not returning all prey to owners, nfc is the number of un-owned cats in the contiguous United States, pfh is the proportion of un-owned cats that hunt wildlife, and fpr is the annual predation rate by un-owned cats.

As not all cats were studied in all seasons due to differences in the timing of recruitment, pet mortality and volunteer drop - out, predation rates were calculated seasonally to maximize sample sizes.

An influx of predators to a fire scar would result in temporarily elevated rates of predation, and potentially even local extirpation.

For years now, ABC has been promoting erroneous and misleading information (e.g., baseless feral cat population numbers, exaggerated / erroneous predation rates, etc.) in their tireless effort to vilify free - roaming cats.

Research conducted in more densely populated areas, or areas where unowned cats aren't entirely reliant on prey for their meals, reveals predation rates far lower than 80 percent, [12] especially for birds.

Despite the scarcity of direct observations, evidence for the existence of large arctic cod aggregations in winter was traditionally derived from the intensive predation rate estimated from the stomach content of marine mammals and birds later in the season (Welch et al. 1992).