Growth Rate, Condition and Survival of Red Grouse Lagopus lagopus scoticus Chicks

Moss, Robert L.; Watson, Adam; Parr, R.; Trenholm, I. B.; Marquiss, M.

doi:10.2307/3676792

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…We suspect that heather seed was readily digested by young chicks as broken seed capsules were frequently found in the droppings and that we are likely to have underestimated the occurrence of these items in the diet. It has been suggested that improved heather growth and flowering in the previous season may indirectly influence chick survival through improved maternal nutrition prior to breeding (Jenkins et al, 1963(Jenkins et al, , 1967Moss et al, 1975Moss et al, , 1981Moss et al, , 1993. Alternatively, it may directly influence chick survival through improved nutrition as heather flowers and seeds were common food items, or it may lead to increased invertebrate densities with similar benefits.…”

Section: Red Grouse Chick Dietmentioning

confidence: 99%

The role of invertebrates in the diet, growth and survival of red grouse (Lagopus lagopus scoticus) chicks

Park

Robertson²,

Campbell

et al. 2001

Journal of Zoology

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The role of diet on the growth, survival and movement of red grouse chicks was examined. We compared two areas of moorland in Scotland; a dry heath with a low density of red grouse and poor chick survival and a wetter heath/bog with relatively higher red grouse numbers and higher rates of chick survival. There were no differences in clutch size, or the proportion of eggs hatching between the two moors but brood survival was significantly lower on the dry heath. Radiotagged hens with broods were monitored during the first 12 days following hatching, the chicks captured, weighed and faecal samples collected. Invertebrate samples were collected within brood feeding ranges. Analysis of chick faeces was used to identify dietary components. Heather comprised the major dietary component on both moors. Invertebrates formed a higher component of diet on the wet moor, and this was positively correlated with growth rates, which in turn were positively correlated with chick survival. We present data from an experiment carried out in 1982, in which chicks showed higher growth rates with increasing insect availability. We also show that broods in which all the chicks survived (4-10 days) had smaller home range areas than broods in which some of the chicks died during this period. We suggest that the differences in chick survival between the two populations was due to variations in the abundance of invertebrates, particularly Tipulids. The protein provided by a high invertebrate component in the diet is, therefore, an important determinant of young red grouse chick growth and survival in some areas.

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Section: Red Grouse Chick Dietmentioning

confidence: 99%

The role of invertebrates in the diet, growth and survival of red grouse (Lagopus lagopus scoticus) chicks

Park

Robertson²,

Campbell

et al. 2001

Journal of Zoology

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“…Counts using dogs were also made in late July-early August. We determined their approximate age from feather development (Parr 1975) and calculated an index of chick condition (Moss et al 1993a). In June and early July when chicks were small, we used trained dogs to find a large sample of broods, caught chicks in hand nets, and weighed and ringed them.…”

Section: The Birdmentioning

confidence: 99%

“…In June and early July when chicks were small, we used trained dogs to find a large sample of broods, caught chicks in hand nets, and weighed and ringed them. We determined their approximate age from feather development (Parr 1975) and calculated an index of chick condition (Moss et al 1993a). A small sample of nests found by radio-marking hens each year provided data on clutch size, egg size (length X breadth 2 in cubic millimetres), hatch date, and chick mass at hatch.…”

Section: Trapping Measuring Marking and Counting Grousementioning

confidence: 99%

“…Previous papers on the Rickarton study area have documented annual variations in the birds' food and nitrogen metabolism ) and the chicks' condition (Moss et al 1993a). These studies have refuted the hypothesis that the observed population cycle was due to host (Red Grouse)-parasite (Trichostrongylus tenuis) interactions (Moss et al 1993b).…”

Section: Introductionmentioning

confidence: 99%

“…Previous papers on the Rickarton study area have documented annual variations in the birds' food and nitrogen metabolism ) and the chicks' condition (Moss et a!. 1993a).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Prevention of a Population Cycle in Red Grouse

Moss¹,

Watson²,

Parr³

1996

Ecology

Self Cite

111

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology. Abstract.Red Grouse (Lagopus lagopus scoticus) show unstable population dynamics.The number shot for sport at Rickarton moor in northeast Scotland, for example, has cycled with 10-11-yr periodicity since 1946. Here, demographic and other causes of a population cycle were documented from 1979-1989, and an experiment tested the prediction that removing some cocks during the increase phase would prevent a subsequent cyclic decline. Throughout the study, sport shooting was stopped on the area where the main work was done. During 1979-1982, before the experimental removal of cocks began, numbers over the whole moor rose from a trough at the start of the study. On the control area, the cyclic peak in 1983 was followed by a decline until 1988, as predicted in advance from models derived from a previous study elsewhere. On the experimental area, enough territorial cocks were removed each spring from 1982 to 1986 to prevent the population from attaining peak densities for five successive years, and no cyclic decline occurred. The removal of cocks resulted in similar numbers of hens being lost from the breeding population. The main demographic cause of population change on control (cycling) and experimental (cycle broken) areas was variation in the recruitment of young cocks to the spring population. On the control area, recruitment was related to cycle phase and breeding success. Changes in food, nitrogen metabolism, and parasite burdens could not explain the cycle. Demographic patterns were consistent with a model in which changes in age structure affected recruitment. These and previous results refute four hypotheses as necessary causes of population cycles in Red Grouse: (1) maternal nutrition, (2) a version of Chitty's genetic hypothesis, (3) hostparasite (caecal threadworm), and (4) predator-prey relationships. The hypothesis that age structure changes and associated behavior cause cycles by affecting recruitment and, thus, population change, remains unrefuted.

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