Provider: - Institution: - Data provided by Europeana Collections- v.39:no.11 (1958)- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 ...Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- v.39:no.12 (1958)- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 ...Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
A shrike for mobility Moore, Peter D
Nature (London),
01/1999, Letnik:
397, Številka:
6714
Journal Article
Recenzirano
Work on fruit-eating lizards from the Canary Islands shows that viable seed can be ingested by the predator with its prey and taken to further destinations, thus adding a new dimension to seed ...dispersal.
Using video cameras, we documented at least two fledgling Loggerhead Shrikes (Lanius ludovicianus) visiting their parent's second active nest. We recorded 70 visits during a 10-day period, with ...visits averaging 7 min. We observed the fledglings sitting on the nest contents on 21 occasions. We concluded that these visits were not indicative of cooperative breeding behavior, because the fledglings were destructive to the nest structure and contents, and the adult female exhibited aggressive behavior toward the fledglings. An early reduction in post-fledging parental care by their father (who was of captive-bred origin) and slow development of the fledglings' hunting skills might have caused them to seek food resources from their mother. However, this is the first time that we have observed these behaviors in this intensively managed population.
In many bird species, males display colourful, usually carotenoid or structurally based plumage ornaments. On the other hand, there are many bird species and entire avian genera that are achromatic, ...i.e. with predominantly white, grey and black plumage colours. Achromatic plumage is a typical feature in many shrikes for example. In this study, we examine the importance of an achromatic plumage pattern, namely, the black tail spots on the two outermost tail feathers (T6 and T5) of Lesser Grey Shrikes (LGS) for sex discrimination and as an indicator of individual quality. Our results suggest that the black tail patterns, especially spots on T5, are important for sex discrimination, but only in combination with other melanin-based or morphological features. The presence of black tail spots on T5 is also an indicator of male age. However, there is no indication that presence, size and asymmetry of these black spots are indicators of individual quality of both sexes in the terms of breeding performances.
1.
1. Great grey shrikes (
Lanius excubitor) are found over much of the Holarctic, including the most severe deserts in the Middle East. We measured operative environmental temperatures of great grey ...shrikes using unheated taxidermic mounts in the field in summer and winter, and calculated standard operative temperatures from these values.
2.
2. Resistance to heat loss in the shrikes was low compared to other small endotherms.
3.
3. Standard operative temperature lies within the thermoneutral zone throughout the shrikes' morning and afternoon foraging periods in summer. In winter, standard operative temperature was below lower critical temperature throughout the day.
4.
4. We found no significant relationship between activity of these shrikes and standard operative temperature in winter.
The vast expanse of North American prairie has been reduced by at least 90% of its original area. As a result, the populations of many grassland birds are in serious decline. This study investigated ...Loggerhead Shrike (Lanius ludovicianus) population trends in Kansas by comparing two Breeding Bird Survey (BBS) routes (16 and 17) in north-central Kansas showing more stable shrike populations, with two BBS routes (06 and 07) in southern Kansas showing more dramatic declines during the last 30 years. With the exception of large increases in pesticide use, there have been few land-use changes the last 30 years along the two northern routes. Along the southern routes, land-use changes include large decreases in pasture, urbanization, loss of tree rows, and large increases in pesticide use. Our land-use survey showed more pasture, woodland, scattered trees and shrubs, and barbed-wire fences in the north, and more wheat, residential areas, and tree rows in the south, indicating significant differences between study areas in key habitat requirements for breeding Loggerhead Shrikes. Our two-year census of the four BBS routes showed a higher density of shrikes in the north (3.0/census) than the south (1.9/census). The habitat associated with shrikes in the north showed a greater amount of pasture and significantly more scattered trees and shrubs compared to the south, where shrike habitats were more heterogeneous and usually associated with tree rows. The nesting success in both areas was relatively low for Loggerhead Shrikes.
