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1.
A. J. F. K. Craig 《Ostrich》2013,84(4):176-180
Craig, A. J. F. K. 1987. Co-operative breeding in the Pied Starling. Ostrich 58:176-180.

Pairs of Pied Starlings Spreo bicolor build the nest, but only the female incubates. After the chicks hatch, subadult and juvenile birds help feed the young. Helpers also feed young after they leave the nest. In most cases parents contribute more than the helpers which may attend several different nests. Associations between members of the same breeding group may persist for up to three successive seasons.  相似文献   

2.
Peter  Ward 《Ibis》1966,108(1):34-40
Quelea quelea is distributed throughout Africa south of the Sahara in the Grass Steppe, Dry Savanna, and Montane Grassland biomes. It is most numerous where its staple food–the seeds of annual grasses–is most plentiful. In all parts of the range, the males in nuptial plumage are dimorphic. Everywhere the “black—faced” morph is commoner, but with up to 25% of “white-faced”. Proportions of the morphs are given for samples from various parts of Africa. Only three races are accepted: quelea of western West Africa, aethiopica of the Sudan area, and lathami of southern Africa. In the Lake Chad basin there are hybrid swarms breeding (queleaj aethiopica), as there are in East Africa where aethiopica/lathami swarms occur.  相似文献   

3.
P. A. Clancey 《Ibis》1967,109(3):318-327
The four major groupings into which the Zosterops forms of southern African can be arranged have for long been treated by conservative systematists as constituting four discrete species (Z. capensis, Z. pallidus, Z. virens and Z. senegalensis). In a major study, published in 1957, Moreau arrived at the tentative conclusion that in zoo-geographical South Africa Z. cupensis and Z. wirens are clearly conspecific, Z. pallidus is a doubtful monotypic species, and Z. senegalais is a polytypic species of wide continental range, specifically segregated from the foregoing on the basis of a wingltail ratio character, and of juxtaposition without evidence of interbreeding. A new study of the complex problem of Zosterops relationships in South Africa based on a critical study of over 900 specimens examined in the Durban Museum, suggests that only two species (Z. pallidus and Z. senegahsis), very closely related and part of the same superspecies, are actually involved.  相似文献   

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5.
Lloyd, P., Hulley, P.E. & Craig, A.J.F.K. 1996. Comparisons of the vocalizations and social behaviour of southern African Pycnonotus bulbuls. Ostrich 67: 118–125.

Vocalizations and associated behaviour of three Pycnonotus species are described, based on field observations and tape recordings from which sonagrams were produced. These species, which are locally sym-patric and hybridize, have similar vocalizations and displays; differences are most apparent in their contact calls and songs. Quantitative analysis of the songs showed that P. barbatus and P. capensis are easily distinguished, whereas the song characteristics of P. nigricans overlap those of both the other species. Playback experiments with territorial male P. barbatus in an area of allopatry showed similar responses to songs of conspecifics and of P. nigricans, but almost no response to the song of P. capensis.  相似文献   

6.
I analyzed geographic partitioning of mitochondrial DNA (mtDNA) restriction-site variants in the spotted salamander, Ambystoma maculatum. Two highly divergent and geographically separate genetic lineages were identified that differed by a minimum of 19 restriction sites (6% sequence divergence). One of the lineages has a disjunct distribution with very closely related haplotypes occurring in Missouri, Arkansas, North Carolina, and Virginia. The other lineage is found in Michigan, Illinois, and Alabama. The geographic separation of highly divergent mtDNA haplotypes, a pattern that was predicted based on the sedentary nature of these salamanders, is evidence for long-term barriers to gene flow. In contrast, the large-scale disjunction of very similar haplotypes suggests recent, long-distance gene flow and does not match the phylogeographic expectation for a small terrestrial vertebrate. I explain this potential contradiction in the level of importance assigned to gene flow by a scenario in which historical barriers to gene flow account for the two divergent mtDNA assemblages, but stochastic sorting of ancestral polymorphism is responsible for the large-scale geographic disjunction. Ten of 16 populations collected in the Ozark Highlands were fixed for the same haplotype. I attribute this lack of detectable variation to recent colonization of this area, a hypothesis that is supported by paleoecological data and demonstrates the potential benefits of combining data from paleobotany, geology, and other disciplines to reconstruct the historical biogeography of a species.  相似文献   

7.
SUMMARY

The distribution of four species of Chaoboras over selected parts of Zimbabwe is given. The effect of temperature on the duration of the larval life cycle is discussed in relation to the generation time and the lunar periodicity of the adult emergence period. There were apparently two generations of larvae present in the habitat at any one time, although these generations were not distinct due to the variations in the time taken by the larvae to complete development at any temperature. The emergence was synchronized to the lunar cycle, but the actual moon phase at which emergence occurred was variable, as the two populations under observation both changed from new moon emergences to full moon emergences during the study. Some observations on the behaviour of adult Chaoboras edulis are given.  相似文献   

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10.
R. A. Earle 《Ostrich》2013,84(3):118-121
Earle, R. A. 1987. Distribution, migration and timing of moult in the South African Cliff Swallow. Ostrich 58:118-121. The South African Cliff Swallow Hirundo spilodera breeds in South Africa mainly between 25 and 31S and 24 and 31E. In some years with exceptionally high rainfall the breeding range is more extensive. Man has probably had a pronounced influence on the present-day distribution of this species. Seven winter recovery/collecting localities are known from the lower Congo basin in Zaire. Possible migrating birds were observed in Zambia and Malawi in the east, and on the Namibian coast in the west. The few sight records suggest a direct migrational route over Botswana. Moult takes place between March and September primarily in the winter quarters, but about 2% of the birds handled during March and April started moult before migrating.  相似文献   

11.
SUMMARY

The yield coefficients and minimum cell concentrations of silica, nitrogen and phosphorus have been determined for four diatoms, Navicula pell iculosa (Brébisson ex Kützing) Hilse, Nitzschia elliptica Hustedt, N. palea (Kützing) W. Smith and N. perpusilla Rabenhorst. It was found that the three Nitzschia species require more Si > N > P whereas the Navicula species needs more N > Si >P. Where possible the results are evaluated in terms of the morphological and ecological characteristics of these diatoms.  相似文献   

12.
Yom-Tov, Y., McCleery, R. & Oatley, T. 1994. The survival rates of some southern African passerines. Ostrich 65:329-332.

Little information is available on survival rates of southern hemisphere passerines, but two recent studies indicate that Australian passerines tend to live longer than their northern hemisphere relatives. The aim of this paper is to provide data on survival of some South African passerines and compare them with Australian data. The survival rates of eleven species (eight genera) of South African passerines were calculated using recapture data provided by the South African Bird Ringing Unit for birds whose retraps occurred more than 12 months after the original ringing. Survival did not depend on either the length of the study or body mass. Mean survival rate was similar to that of 32 species of Australian passerines, which is at least 1,2 greater than that of British passerines.  相似文献   

13.
14.
In coccidioidin skin test surveys among persons of high school age in Saugus, Canoga Park, Banning and Palm Springs areas the average incidence of positive reaction was 15 per cent. Although considerably less than the 68 per cent incidence reported among high school students of Kern County, it is high enough to indicate pockets of relatively high endemicity in Southern California below the San Joaquin Valley.Histoplasmin tests were performed on most of the persons tested with coccidioidin in this survey. The over-all incidence of positive reaction in the group was 7.6 per cent. Most of the subjects with positive reaction to histoplasmin gave a history of having previously lived in some area in the central United States where histoplasmosis is known to be endemic.A few subjects who had positive reaction to coccidioidin tests and who had lived in areas known to be endemic for coccidioidomycosis but not for histoplasmosis, also had positive reaction to histoplasmin. However, the induration produced was always smaller than that caused by the coccidioidin reaction, and there was minimal confusion in interpreting the tests.  相似文献   

15.
ANNA MOTIS 《Bioacoustics.》2013,22(2):119-141
ABSTRACT

This paper describes the whistled songs of two allopatric populations of the European starling and spotless starling in NE Spain. The results show that European starlings in NE Spain sing the same whistled themes found earlier in other European populations and confirm the universal character of these themes. There are some differences between European starlings from NE Spain and other populations: rising phases appear for Inflection theme high-form, Inflection theme and Simple theme, and also differences of rate of emission appear for others (Rhythmic theme). Harmonic theme has not been found. Likewise, the first analysis of the spotless starling's whistled song shows that it shares the same general whistled song structure with the European starling; whistles have similar structural parameters (modulation, duration, frequency) and can be classified in the same categories or themes; a new theme appears, the Trilled theme, which has not been found to date in the European starling. Dialectal areas have been found in both species for the same themes (Inflection theme, Simple theme). The males of both studied populations have larger repertoires in comparison to other studied populations of the European starling.  相似文献   

16.
SUMMARY

An additional 13 species of freshwater fishes recorded from south-western Angola, mainly from the Cunene Basin, are added to the checklist of southern African freshwater fishes, including five species of marine origin permanently resident in the fresh water of the Cunene River mouth. In addition, attention is drawn to a number of doubtful records from the region. A gazetteer of collecting localities in the region is presented.  相似文献   

17.
SUMMARY

Alterations and additions to the checklist of southern African freshwater fishes are given based on recent findings and the latest literature. Name changes are given for 13 taxa, and 25 species and subspecies are added to the list. Several species of marine origin (peripheral species) which form an integral part of continental fish communities in coastal lakes and low salinity lagoons are included in the checklist.  相似文献   

18.
Cooper, J., Brooke, R.K., Cyrus, D.P., Martin, A.P., Taylor, R.H. & Williams, A.J. 1992. Distribution, population size and conservation of the Caspian Tern Sterna caspia in southern Africa. Ostrich 63: 58–67.

The Caspian Tern Sterna caspia occurs along the whole southern African coastline and on large river systems and water bodies away from the coast. A total of 28 definite breeding localities has been recorded in southern Africa. Breeding has occurred recently at at least 14 coastal localities between Swakopmund, Namibia, and Lake St Lucia, Natal, South Africa. Inland breeding has been recorded in recent years at Sua Pan, Botswana and Kalkfonteindam, Orange Free State, South Africa. Based on censuses conducted between 1980 and 1991, the southern African breeding population is estimated to be of the order of 500 pairs, 91% of which breed coastally and 89% breed on islands. Up to 290 pairs (58%) bred at Lake St Lucia. Seventyone per cent of the 1980–1991 breeding population falls within eight nature reserves. Conservation of the Caspian Tern in southern Africa requires protection at breeding localities, including commercial salt and soda ash extraction works, against the effects of changing water levels, human disturbance and predation. Pesticide levels of addled and abandoned eggs should be measured at selected breeding localities.  相似文献   

19.
20.
The seasonal distribution and abundance of harbor seals occurring south of Maine were documented by counting the number of seals at traditional haulout locations. The average number of seals counted during each survey in Massachusetts and New Hampshire was 3,560 ± 255 (95% CI), 1983–1987. The maximum number of seals counted on any individual survey was 4,736 individuals. Fifty percent of all the surveys since January 1985 have resulted in counts greater than 4,000 seals reflecting a 27% increase in the abundance of seals in our study area since that date. Seventy-five percent of the seals in southern New England are located at haulout sites on Cape Cod and Nantucket Island. The largest aggregation of seals in the eastern United States occurs mid-winter at Monomoy Island and adjacent shoals. A single high count of 1,672 seals occurred at this site during the study period. An additional 271–374 seals were also counted in Rhode Island, Connecticut and eastern Long Island Sound during surveys conducted in March 1986 and 1987. The American sandlance Ammodytes americanus was the single dominant prey item of harbor seals in waters adjacent to Cape Cod based on the modified frequency of occurrence of each prey species in scat samples collected from three haulout sites on Cape Cod between 1984–1987. During January and February sandlance was the near exclusive prey item at Monomoy (99%, n= 80). During March and April, the frequency of Atlantic herring Clupea harengus increased in the scat samples at this site. Regional differences in the diet of seals reflect distinct prey communities throughout the study area. Since 1986, the percent occurrence and importance of sandlance in the diet of seals has decreased, reflecting an overall decrease in abundance of this prey species in waters adjacent to Cape Cod. In spite of fluctuations in abundance, and regional differences in the diet of seals throughout the study area, sandlance still comprised a minimum 55% of the total prey species of harbor seals throughout the study area.  相似文献   

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