Archive for August 25th, 2006
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Swallows were traditionally cave nesters, building mud nests on ledges in caves, and even inside hollow trees. Since Neolithic times they used artificial habitats and now most nest around human habitation. The close association with people has allowed the bird to expand its range greatly through the availability of new sites.
They prefer to nest in association with domestic animals, most often in cow and pig sheds and stables. They sometimes nest under bridges, in wells and mineshafts, and even chimney stacks. They occasionally use very odd sites, including inhabited rooms and regularly moving vehicles.
Swallows are not truly colonial, but as nest choice primarily depends on food availability, several pairs can nest close together in loose groups, although single nests are most common.
Swallows return to Britain in April and May. The males return ahead of the females to claim nest sites. The main breeding season runs from April to August, when insects are most abundant, although late broods can be found still in the nest in September. During this time the birds raise two broods, sometimes three.
The nest is a deep bowl of mud mixed with grass and bound together with saliva, built by both birds on top of a rafter or another suitable ledge inside a building or under an overhang. The feather lining is added by the female. Building of a new nest takes about a week, but birds tend to re-use the previous years nest where possible.
The 4-5 eggs, white speckled with reddish brown, are laid at daily intervals, although bad weather can delay laying. The female incubates alone for 14-16 days and broods the young for the first week of their life, while they are naked and unable to maintain their own body temperature. The male shares the feeding duties until the brood is independent. In good conditions the brood will fledge at 21 days, but bad weather can slow down their development and delay the fledging.
From 70 to 90% of eggs laid produce fledged young in a good year, although in years of cold wet weather food shortage can be a major cause of mortality. After fledging, the broods stay in family groups for another week or fortnight, when they are fed by their parents and return to the nest to roost. Fledged young from first broods often help their parents feed a second brood.
The autumn migration takes place in September and October. Juveniles and adults travel together and family groups sometimes stay together on migration.
Nest sites are traditional, and provided the food supply has not changed, the same nests or sites are used from one year to the next, frequently by the same two birds. Swallows breed when they are one year old, many returning to breed within 3 km of the nest they fledged from most birds within 30 km. They are short-lived birds, and most live fewer than four years. The maximum recorded age is 16 years.
August 25th, 2006
ORNITOLOGIA NEOTROPICAL 9: 209–212, 1998 © The Neotropical Ornithological Society
Salvador Peris & A. Llanes1Department of Animal Biology-Zoology, Faculty of Biology, University of Salamanca, 37071 Salamanca, Spain. 2Institute of Ecology and Systematic. Ministry of Science, Technology and Environment of Cuba.
209 INTRODUCTION Following to Ridgely & Tudor (1989), we considered the Cave Swallow (Hirundo fulva) as a species distinct from the Chesnut-collared Swallow (H. rufocollaris), which has breeding populations in Ecuador and Perú. The Cave swallow breeds in Central America, the Caribbean and in the southern U.S. The species is widely distributed in Cuba and the Juventud Isle (fomerly called Isle of Pines), where it breeds on farm-houses, factories, sea cliffs and in natural caves (Bond 1990), wintering in small flocks in the country (Garrido 1988). In spite of its relative abundance, little is known of its breeding biology in the Caribbean. The aim of this study is to provide information on the breeding biology of two Cave Swallow populations in two different habitats of central Cuba. STUDY AREA AND METHODS Observations were made in the caves of Beruvides-Sebastián, located 1.5 km east of the village of Agramonte (22°40’N, 81°08’W), province of Matanzas (central Cuba). The other colony, also located in the Matanzas province, was situated on a high factory building in San Antonio de Los Baños (23°03’N, 81°31’W). Both localities are situated in a mixed urban-agricultural area. The colonies were monospecific, without association with other swallow species, as has been fund elsewhere (Huels 1985). The caves of Agromonte have numerous escarpments, which the swallows use to attach their nests. The nests of the San Antonio colony are fund on the top of roof beam. In both colonies, a mist-net 9 x 2 m, was set up during the morning at the entrance of the caves and building, from 20 March to 22 December 1993; a total of 215 birds were captured. Most of the birds were weighed, measured, banded with a U.S. Fish & Wildlife Service aluminum ring and released afterwards. The following measurements were taken
GENERAL BIOLOGY following Svensson (1984): wing length (flattened and straightened), tail, tarsus length and bill length (from the nostrils to the tip of the bill). In April, the birds were sexed using as criteria the presence or absence of an incubation patch and the morphology of the cloacal protuberance. Nest measurements included height above the ground, external maximum diameter, internal maximum diameter and depth of the nest ́s concavity. Eggs were measured (length and width) with a slide caliper to the nearest 0.1mm. Egg weight was obtained by a Pesola balance to the nearest 0.5 g and only in the first three incubation days. Statistitests (Fowler & Cohen 1987). RESULTS AND DISCUSSION Measurements and morphology of the breeding birds. No apparent sexual dimorphism was found in plumage characters. Although males were slightly larger than females, no significant differences (mean ± SD; P > 0.05) were found between the sexes in body mass: male 17.6 g ± 1.2, female: 17.6 g ± 1.4; wing lenght: male 102.1 mm ± 0.2, female: 101.3 mm ± 0.1; tail length: male 41.0 mm ± 0.2, female 41.4 mm ± 0.2; tarsus length (12.7 mm ± 0.0) and culmen length (5.5 mm ± 0.0), nor between the birds from the two study localities. Brood patches were present in all the females captured from late April to early August. This patch is not so well developed in males, being a useful character in sexing swallows (Fig. 1). Cloacal protuberance is only slightly marked in females, but it is well developed in males (Fig. 1), being also a good character for sex discrimination during the breeding season (late April to early August). The eggs size were measured only in one locality (Agromonte): mean length = 20.5 mm ± 0.1 (CV = 5.0), width: 14.5 mm ± 0.1 (CV = 3.2), and fresh weight = 2.1 g ± 0.2 (CV = 1.9). Molting of the inner primaries began in both sexes from early-middle June to middle December, reaching its maximum during September and October, when all the captured birds were moulting (Fig. 2). Comparison between nests in natural caves and factory buildings. Median height of the nests above the ground in natural caves was very similar to those measured in buildings (Table 1). Nests from the human settlements in San Antonio have significantly larger diameters and width than these situated in the caves (Table 1). Depth and height of the nests were similar in both localities, but which a statistiFIG. 1. Percentage of occurrence of cloacal protuberance and brood patch according to seasons, in breeding Cave Swallows from Matanzas (central Cuba). FIG. 2. Percentage of Cave Swallow individuals molting in Matanzas, central Cuba.SHORT COMMUNICATIONS Although height and depth are important parameters in nest-boxes nesting birds in order to increase the number of eggs and nestlings (East & Perrins 1988, Pascual 1994), also the nest width could implicate differences in clutch size. Unfortunately, clutch size in the San Antonio colony was impossible to record and no comparisons with the Agromonte colony (with an average clutch size of two eggs by nest) are possible. The larger structural dimensions of the nests in the factories may be due to their support on beam-buildings with the need of larger and more robust nest-material on these structures without walls. In contrast, the nests on natural depressions are firmly attached to the rocky walls and do not need the support of large material. However, Martin & Hector (1988) observed the use of wool as a lining material in the nest of cave swallows in Texas (US) with potential negative effects on the breeding perfomance of the birds due to lack of proper nestling thermoregulation. In our populations no lining material of human origin was observed, in spite of the nearby high population density in both localities. However, if temperature has an indirect effect on nest-building (Elkins 1983) the differences found in nest ́s size could indicate the warmer environment of the buildings, and a need for larger nest structure in order to avoid hyperthermia, in comparison with the ACKNOWLEDGMENTS Manuscript was improved by an anonymous reviewer. Partial funding was provided by the Instituto de Ecología & Sistemática, Ministry of Science, Technology & Environment of Cuba and the Universidad de Salamanca of Spain. REFERENCES Bond, J. 1990. Birds of the West Indies. Collins, Hong-Kong. East, M. L., & C. M., Perrins.1988. The effect of nestboxes on breeding populations of birds in broadleaved temperate woodlands. Ibis 130: 393–401. Elkins, N. 1983. Weather and bird behaviour. Poyser, Calton, U.K. Fowler, J., & L. Cohen. 1987. Statistics for ornithologist. BTO Guide 22. Tring, U.K. Garrido, H. H. 1988. La migración de las aves en Cuba. Publ. Asoc. Amigos de Doñana no 0. Sevilla. Huels, T. R. 1985. Cave Swallow paired with Cliff Swallows. Condor 87: 441–442. Martin, R. F., & D. Hector.1988. Nest lining with sheep wool. Potential negative effects on cave swallows. Wilson Bull. 100: 294–296. Pascual, J. A. 1993. Ocupación de distintos modelos de nidal por el Estornino negro (Sturnus unicolor). Doñana Act. Vertebrata 20: 165–178. Ridgely, R. S., & G. Tudor. 1989. The birds of South America. The oscine passerines. Univ. of TABLE 1. Cave Swallow nest measurements (mm) at two study localities in Matanzas Province, Cuba. San Antonio (n = 32) Agramonte (n = 35) t-test Width 154.7 140.2 2.095* Internal diameter 87.0 72.0 4.002** External diameter 113.4 103.0 2.282** Depth 46.4 40.9 1.776 ns Height 72.0 74.7 0.499 ns *P < 0.05; **P < 0.01.GENERAL BIOLOGY Svensson, L. 1975. Identification guide to European passerines. Naturhistoriska Riskmuseet, Stockholm.
August 25th, 2006
kmtrip.net
Known as one of “the biggest and most splendid cave in Asia”, the Swallow Cave Scenic Region is located in the mountains 30 km east of Jianshui, and consists of a dry cave, a water cave and a 30,000-square-meter natural forest, with a total area of 100,000 square meters. Every year between spring and summer, thousands of swallows will fly here from Malaysia, building nests and giving birth to and raising young swallows. Thus it is named “the Swallow Cave”. The local environment is a perfect dwelling for swallows because steep cliffs make it impossible for mice and snakes to come up, and bushes and grassland outside the cave help produce insects that provide abundant food for swifts. The special ecosystem makes a grand scene-”the gathering of thousands of swallows”.
Swallows build their nests with grass and their nutritious saliva. The steamed swallows ‘nest is a delicacy-edible bird’s nest. Every year from August 8 to 10 during the famous “Bird’s Nest Festival”, some local people will climb up the dazzling 50-meter-high cliffs to fetch these nests. During the three days, many people will gather here and watch the dangerous but exciting nest-collecting activity.
Every year on March 21, another special but even more dangerous and exciting activity is the board-hanging ceremony. As a rule, firecrackers are let off to express people’s good wishes to climbers. Then in a merry atmosphere, those brave men slowly and carefully climb up, barehanded. Although it is very dangerous, no one has failed to hang a board onto the top. Nowadays, over 1,000 boards hang on the stalactites over the entrance, some of which have been there for generations.
Inside the Swallow Cave, there is a tourist track of about 3,000 meters. The upper part is a dry cave and the lower part is a water cave. Along the track, there are three main scenic areas, namely, “Exploring Along Dragon Spring”, “Picking up Beauty in Heavenly Streets” and “Wonder Land”. The total tourist area reaches 40,000 square meters. Entering the cave, steeping up the stairs on the left and passing through a narrow cave, one arrives at the “air veranda”, which gives people a dazzling feeling. The scene in the water cave is marvelous as well, which a 50-meter-high and 30-meter-wide entrance. The Lujiang River pours into the cave through the entrance as its underground river. Experts have proved that the water cave has had a history of three million years. Due to the wash of water, stalactites of different shapes have come into being. The dry cave is shaped like a grand hall, big enough to contain 1,000 people. It is a place for rest and for watching local performances. At the exit, three different pieces of the sky can be seen at three different positions. This is another unique scene, which adds luster to the cave.
August 25th, 2006