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Aspects of the ecology and behaviour of the rook Corvus frugilegus L. were studied. The decline of rook populations in Britain since the 1940's is documented and the extent and reasons for the decline in north east Fife examined in detail. The most likely causes of this were changes in agricultural practices, including the way the land is used and possibly the use of organo-chlorine insecticides. The ecological relationship between the rook and the carrion crow C. corone L. is explored in an investigation of their habitat use and associated niche metrics. Both species are heavily dependent on agricultural land, especially grassland, for foraging. The carrion crow narrows its niche breadth more than the rook does at times of possible food shortage. Observations on captive birds show rooks to be subordinate to carrion crows. Analysis of nestling rook gizzard contents revealed cereal to be an abundant food as well as invertebrates, particularly beetles and tipulids. A review of tool-use in birds is presented and the conditions under which tool-use is likely to arise are elucidated. The proximate causation of an example of this category of behaviour performed by at least one captive rook is reported. The rook is identified as an ecologically and behaviourally adaptable bird.

This thesis aims to fill gaps unfilled by the recent upsurge in Chough studies. These are: the classification and functional analysis of aspects of their behaviour, examining feeding preferences in relation to land management, finding how literary attitudes towards them developed and obtaining quantitative insights into their past distribution to apply to possible explanations for their status changes. Three pairs near Llangranog, Dyfed were observed and findings were complemented with analysis of RSPB film offcuts. All observed behaviours were defined and classified according to social context and frequency of use. Of 45 behaviours seen, 21 had not previously been recorded. Single-link cluster diagrams were presented to illustrate observed postures and comparable corvid postures. Three aspects of their social behaviour were further examined: Food-begging by juveniles and females was related to time since fledging and copulation date respectively. Begging success depended on technique repertoire, which increased with time; increased foraging group size decreased the individual's vigilance time spent, with an earlier detection of potential tourist disturbance; wing-flicking did not occur with short flights nor after flights due to disturbance. It was frequent after landing while as frequent before take-off as during foraging excepting tourist disturbed flights. Ritualised forms of wing-flicking and bill-wiping formed the basis of Chough communication. Flow diagrams and canal models describing the functional organisation of these behaviours are presented. Choughs feed on short, mainly grass swards maintained by grazing, exposure and occasionally, cutting. When given the Jackdaw's old name, Choughs acquired their thieving reputation and were also regarded as fire-raisers until the 1830's. Distribution and abundance from 1750 to 1982 were estimated at county and national level. Their status was not significantly affected by climate. Grazing artificially boosted their numbers, agricultural changes and persecution from 1750 until 1940 caused their decline.

Thesis (Ph. D.)--University of Wyoming, 2007. / Title from PDF title page (viewed Feb. 9, 2009). Includes bibliographical references.

In previous studies with stuffed dummies, we found interesting difference in nest defence of Red-Backed Shrike (Lanius collurio) against two similar nest predators: Jay (Garrulus glandarius) and Magpie (Pica pica). Jay was attacked very intensively, whereas Magpie almost wasn´t hited and Shrikes seemed to keep in cover. Here, I describe the antipredation behavior of the Red Backed Shrike against another stuffed corvids presented closely to Shrikes nests: Jay (Garrulus glandarius), Common Nutcracker (Nucifraga caryocatactes), Rook (Corvus frugilegus), Crow (Corvus corone) and Raven (Corvus corax). I found Jay and Nutcracker to be attacked by Shrikes very strongly, whereas Rook, Crow and Raven were attacked rarely (Shrikes only flied around them or sit at a distance, watching the dummy, sometimes accompanied with alarm-calls). Shrikes response is affected mainly by kind of predator, by age of youngs and by quality of concealment of nest. More - www.mn.ic.cz