Archive for January, 2008
linkinghub.elsevier.com
Nicola Sainoa, f1, Paolo Galeottib, f2, Roberto Sacchib, f2, Giuseppe Boncoraglioa, Roberta Martinellia and Anders Pape MĆøllerc, f3
a Dipartimento di Biologia, UniversitĆ degli Studi di Milano
b Dipartimento di Biologia Animale, UniversitĆ degli Studi di Pavia
c Laboratoire de Parasitologie Evolutive, CNRS UMR 7103, UniversitƩ Pierre et Marie Curie
Received 10 October 2002;Ā revised 25 November 2002;Ā accepted 20 March 2003.Ā ; Available online 13 November 2003.
Abstract
Parents of sexually reproducing species should adjust their investment in production of sons and daughters in relation to the relative costs and reproductive value of offspring of either sex. Sex allocation mediated by differential allocation of care such as food provisioning, however, requires that parents can identify offspring sex. We analysed sex differences in offspring begging calls that may serve as a cue for parents to discriminate between sons and daughters. A combination of three sonagraphic variables of begging calls of nestling barn swallows allowed us to classify them according to sex at day 16, but not at day 12 after hatching, suggesting that sex differences in begging calls arise during the nestling period as the time of fledging approaches. Hence, parents may be able to discriminate between sons and daughters by auditory cues, which would enable differential allocation of food between offspring during the late nestling and early fledging stages. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.Ā
f1 Correspondence: N. Saino, Dipartimento di Biologia, UniversitĆ degli Studi di Milano, Via Celoria 26, I-20133 Milano, Italy (email: nicola.saino@unimi.it
f2 P. Galeotti and R. Sacchi are at the Dipartimento di Biologia Animale, UniversitĆ degli Studi di Pavia, P.zza Botta 9, I-27100 Pavia, Italy.
f3 A. P. MĆøller is at the Laboratoire de Parasitologie Evolutive, UniversitĆ© Pierre et Marie Curie, 7 quai St. Bernard, F-75252 Paris, France.
January 17th, 2008
www.longchuenbirdsnest.com
Ingredients:
113 g superior birdās nest, soaked until soft and stewed
113 g broccoli
carrot, diced
3 cups stock
Seasoning :
1/4 tsp salt
2 tbsps water chestnut powder
4 tbsps water
Method
1. Cut broccoli into short sections, soak in diluted salty water for a while and rinse. Parboil and rinse broccoli and carrot dices.
2. Bring stock to the boil. Add birdās nest, broccoli and carrot dices and cook for 5 minutes. Combine with seasoning and dish up. Serve.
January 16th, 2008
www.ornitologia.org
OĢscar Gordo
The abnormal behaviour of a group of Barn Swallows roosting in a maize field is described in detail. Approximately 700 individuals forming a spherical flock performed spectacular manoeuvres over a maize field for several minutes.
After sunset, individuals plunged vertically in small groups into the maize field in very fast flight. Observed behaviour agreed largely with previously reports, although some peculiarities were recorded such as an attempt to roost on sparsely grassed ground, attacks by Yellow Wagtails Motacilla flava on landing swallows and loud twittering during all the aerial manoeuvres. The bad weather conditions are the most likely cause for the roosting of these migrating individuals. Key words: Barn Swallow, Hirundo rustica, roosting, behaviour, maize field, autumn migration, NE Spain Current address: OĢscar Gordo, Dept. EcologiĢa Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), c/JoseĢ GutieĢrrez Abascal, 2, 28600 Madrid. E-mail: ogordo@mncn.csic.es Received: 17.04.06; Accepted: 03.04.07 / Edited by L. Brotons
Communal roosts are typical in the Barn Swallow Hirundo rustica outside the breeding season. In African wintering quarters, large numbers of Barn Swallows are found in a small number of roosting sites, in which thousands or even millions of birds congregate every evening (Vrijdagh 1951, de Bant 1962, Curry-Lindahl 1963, van den Brink et al. 1998, 2000, Deuzeman et al. 2004). These huge aggregations occur typically in reed-beds close to rivers and lakes (Verheyen 1952, de Bant 1962, Curry-Lindahl 1963, van den Brink et al. 2000, Nutall 2000; but see also Cramp 1988, Fry et al. 1988, Nutall 1998), where birds can forage nearby. This gregariousness also benefits individuals as a means of reducing predation risk (Bijlsma & van den Brink 2005). Roosts have been also reported in European breeding grounds, above all in late summer and autumn (Cramp 1988). In these cases, Barn Swallows have been recorded in different types of habitats (e.g. bracken, James 1995; reed-beds, Kose 1993) and also locations such as maize fields on several occasions (Ford & Elphick 1993, Lukac 1994, Spence 1995). These postbreeding roosts are thought to be associated with increased predation risk and/or bad weather conditions (Stagg 2005). Here, the unusual behaviour of a roosting flock of Barn Swallows observed on 29 September 2005 is described in detail. The observation took place in an area of open ground of 40 ha named Pla de Can MoratoĢ, between the villages of Cardedeu and Sant Antoni de Vilamajor (ValleĢs Oriental; UTM 447-4610) at 210 m a.s.l. in NE Spain. The area is covered by a mosaic of crops, pastures and small patches of Pinus pinea woodland, all of which are surrounded by builtup areas and mixed forest. Most of the area was lying fallow at the time of observation and only a maize field of ca. 2 ha was still unharvested. These plants were approximately 1-1.5 m high. The observation took place in the evening between 18:50 h and 20:10 h in bad weather conditions, with a dense cover of dark clouds, intermittent gusts of wind and some rain between 18:55 and 19:05 h.
At 18:50 h, approximately 100 Barn Swallows appeared in the area and apparently began to forage near the ground (maximum 10 m high). When it started raining five minutes later, more individuals arrived from nearby built-up areas, increasing the number of individuals to ca. 200. When it stopped raining, all of the birds suddenly disappeared northwards. A few minutes later (19:10 h) a large number of birds (about 300) re-appeared. However, on this occasion, all of the birds were flying together in a compact flock that then proceeded to move northwards and southwards, performing spectacular manoeuvres over the fields of Pla de Can MoratoĢ. At 19:20 h most of the Barns Swallows began to land on open ground. A number of Yellow Wagtails Motacilla flava, which are regular visitors in small groups of 10-20 individuals to this area during both during spring and autumn passages, attacked the swallows that were attempting to land. Five minutes later all of the swallows took off and formed a compact flock that once again began to perform spectacular aerial movements over the fields. A single Sand Martin Riparia riparia was detected among swallows. At 19:35 h a strong wind from the north (4-5 on the Beaufort scale) dispersed the swallows, which disappeared for ten minutes. The sun set at around 19:40 h, but the swallows soon returned (19:45 h), forming a compact spherical flock, in which birds whirled very fast about 10 m high above the maize field. Unlike the flocks described previously, this group was very noisy. For a few minutes, many individuals arrived from different directions and joined the flock. Eventually, the flock totalled approximately 700 individuals and continued its perfectly synchronised high-speed spiral flight. At 19:55 h small groups of birds (about 20-50 individuals) began to plunge vertically into the maize field at great speed. By 20:00 h all birds were perched in the maize, concentrated in just a few plants in an area of around 30 m 2 in the middle of the field. An intense twittering continued for a few minutes. Some aggressive interaction between individuals was observed, which resulted in some individuals flying from one plant to another. After perching, all individuals began to preen. At 20:10 h the twittering began to fade and I left the area. Similar incidents of birds on autumn migration roosting communally in a maize field have never been observed in the same place either before or subsequently: it was, thus, an isolated and exceptional incident, probably caused by adverse weather conditions (Stagg 2005). This fact could explain the differences between the observed behaviour, that is, the attempts to roost on open ground, the aggressive response by Yellow Wagtails and the aerial manoeuvres with much twittering, and the descriptions of roosting behaviour in Cramp (1988). However, the type of habitat used finally to roost in (Ford & Elphick 1993, Lukac 1994, Spence 1995) and the presence of Sand Martins (Cramp 1988) both agree with previous descriptions. Resum Comportament inusual dāun grup dāorenetes Hirundo rustica durant la migracioĢ de tardor abans dāajocar-se Es fa una descripcioĢ detallada del comportament dāun grup dāunes 700 orenetes vulgars abans dāajocar-se en un camp de blat de moro. Van formar un estol de forma esfeĢrica i durant varis minuts van fer tota mena de vols sincronitzats forcĢ§a espectaculars per sobre de lāaĢrea on finalment van aturar-se. DespreĢs de la posta de sol, alguns individus van anar baixant en grups petits amb vols molt raĢpids per anar a parar-se sobre les plantes de blat de moro. Els comportaments observats es corresponen en general amb el que ja es coneixia, tot i que es van observar alguns fets ineĢdits, com ara: un intent dāaturar-se al terra, lāatac de les cueretes grogues Motacilla flava durant aquest intent i el continu soroll dels individus durant tot el proceĢs. Aquests individus en pas van haver dāaturar-se probablement a causa de les condicions meteoroloĢgiques adverses. Resumen Comportamiento inusual de un grupo de golondrinas comunes Hirundo rustica durante la migracioĢn de otonĢo antes de acceder al dormidero Se hace una descripcioĢn detallada del comportamiento de un grupo de unas 700 golondrinas comunes antes de acceder a un dormidero situado en un campo de maiĢz. Formaron un bando esfeĢrico que durante varios minutos realizoĢ todo tipo de vuelos sincronizados muy espectaculares por encima del aĢrea en la que finalmente se posaron. DespueĢs de la puesta de sol, algunos individuos fueron bajando en peque nĢos grupos mediante vuelos muy raĢpidos a posarse en las plantas del campo de maiĢz. Las observaciones corresponden en general con lo anteriormente descrito, pese a que se observaron algunos hechos ineĢditos: el intento de posarse en tierra, el ataque de lavanderas boyeras Motacilla flava durante dicho intento y el ruido continuo de los individuos durante todo el proceso. Las condiciones meteoroloĢgicas adversas probablemente fueron la causa de que estos individuos en paso se pararan. References Bijlsma, R. G. & van den Brink, B. 2005. A Barn Swallow Hirundo rustica roost under attack: timing and risks in the presence of African Hobbies Falco cuvieri. Ardea 93: 37ā48. De Bont, A. F. 1962. Composition des bandes dāHirondelles de chemineeĢ, Hirundo rustica rustica L., hivernant au Katanga et analyse de la mue des reĢmiges primaries. Gerfaut 52: 298ā343. Cramp, S. 1988. The birds of the Western Palearctic. Vol. V. Oxford: Oxford University Press. Curry-Lindahl, K. 1963. Roosts of Swallows (Hirundo rustica) and House Martins (Delichon urbica) during the migration in Tropical Africa. Ostrich 34: 99ā101. Deuzeman, S. B., van der Have. T. M., de Nobel, W. T & van den Brink, B. 2004. European Swallows Hirundo rustica and other songbirds of wetlands in Ghana, December 1997. WIWO report 80: 1ā59. Ford, A. A. & Elphick, D. 1993. Barn Swallows roosting in maize. British Birds 86: 95-96. Keith, S. & Urban, E. K. & Fry, C. H.1988. The Birds of Africa. Vol IV. London: Academic Press. James, R. M. R. 1995. Barn swallows roosting away from water, low down in bracken. British Birds 88: 226ā227. Kose, M. 1993. Swallows roost in reedbeds. Eesti Loodus 8: 270ā272. Lukac, G. 1994. Kultura kukuruza, Zea mays, nociliste lastavice pokucarke, Hirundo rustica. Troglodytes 7: 72. Nuttall, R. J. 1998. European swallows roosting in suburban Bloemfontein. Mirafra 15: 37ā38. Nuttall, R. J. 2000. European swallow roosts in the Memel District, Free State, South Africa. Mirafra 17: 57ā58. Spence, I. M. 1995. Swallows roosting in maize. Welsh Birds 1: 35. Stagg, A. 2005. Hirundine cold-weather behaviour. British Birds 98: 264. van den Brink, B., Bijlsma, R. G. & van der Have, T. M. 1998. European songbirds and Barn Swallows Hirundo rustica in Ghana: a quest for Constant Effort Sites and swallow roosts in December/January 1996/97. WIWO report 58: 1ā55. van den Brink B., Bijlsma R. G. & van der Have T. M. 2000. European Swallows Hirundo rustica in Botswana during three non-breeding seasons: the effects of rainfall on moult. Ostrich 71: 198ā204. Verheyen, R. 1952. Nos hirondelles (Riparia riparia, Delichon urbica, Hirundo rustica) dans leus quartiers dāhiver. Gerfaut 42: 92ā124. Vrijdagh, J. M. 1951. Comportament des Hirondelles de chimeneĢe dans leur quartier dāhiver, au Nord du Congo Belge. Gerfaut 41:177ā195.
January 15th, 2008
hawkeye.ca
Cliff swallows are slender, sleek birds well known for their long migration. Cliff swallows spend their winters in South America and summers in North America. They arrive in or around April
They are very territorial and will always attempt to come back to the same nesting site. The cliff swallow has made a very successful switch from cliffs to manmade structures for nest
placement. Increased insect population from modern agriculture and shelter created by manmade structures are two reasons given for this transition. The cliff swallow now faces strong competition from the introduced house sparrow for food and shelter. This may be why their numbers appear to be dwindling. The cliff swallow is a protected species and their arrival is a sign of spring for many.
Damage
Cliff swallows can be a major nuisance in suburban areas due to their nestling habits. The mud nests damage and deface the outer walls and eaves of residences and office buildings. Building sides often end up smeared with feces from the bird colony along with collecting on the ground. Parasites have been known entering the building through cracks next to the nests.
Control
Cliff swallows enjoy special protection under the law. Only a permitted company like Hawkeye can disturb them once they have built their nest. Controls include; Falconry, capture netting. A good way to eliminate cliff swallow problems is to take down the nests in the winter while they are gone and exclude them from returning using exclusion netting.
Physical Description
The Swallow has a dull forehead; blue-black back, crown, wings and tail; brownish red face and throat; and a white belly. Look for a squared off tail (barn swallows have forked tails) and a pale yellow rump (purple martins have a solid colored back). Juveniles have similar coloring but duller.
Nesting
They build elaborate nests out of mud pellets. The cliff swallow packs mud pellets in the upper eaves of a building. The resulting nest will resemble a wine carafe or flask with the opening on the side. They line the nest with grass and feathers. Nests are packed together in close knit colonies. The colonies range in size from a few to several thousand. Breeding Cliff swallows have two broods per year with each brood containing four to five eggs. Egg coloration will be white, cream or pale pink with brown spots on some of the eggs. The eggs take 12 to 14 days to hatch. Fledglings leave the nest after 25 days.
Cycles
Cliff Swallows migrate each year between North and South America. They winter in South America and summer in North America.
Bird Facts
Height/Weight - 4/1 oz Life Span - 4-6 years in the wild and up to 12 years in captivity Flight Speed - 15-45 mph Range - across country rural to urban areas Food - well noted insects eater Habitat - Suburban areas adjacent to open fields and water.
January 11th, 2008
www.helium.com
The Tree Swallow is one of North Americas most common birds. Tree Swallows are found in most parts of North America, however they will spend their winters in the most southern states and cross over into Central America as well.
The Tree Swallow is a small bird, averaging 5-6 inches long with a wingspan of 12-14 inches. They have forked tails and their beaks are extremely tiny. These small song birds prefer marshes and open fields, but can be found in suburban areas as well. The Tree Swallow is a migratory bird. They breed during warm weather in North America, and spend their winters in Mexico, Central America and the Caribbean. Both the male and female Tree Swallow have beautiful blue-green feathers on their backs, with a white belly, however young yearling females are brown.
Tree Swallows throughly enjoy making use of nesting boxes that many people have in their yards. They are cavity nesters, and will nest in natural or artificial cavities. Tree Swallows do prefer to be near a water source and often travel and live in large flocks. If you are looking to attract wild birds to your yard, you will probably have great success in attracting Tree Swallows. Do to deforestation, there are far fewer nesting sites for Tree Swallows, so they will readily seek out any artificial dwellings that you may put out. Tree Swallows will then build their nests of grasses and twigs within these dwellings. An interesting fact about the Tree Swallow nest is that they prefer using feathers from other birds in line their nest to help keep their young warm and also help keep the level of parasites and mites low as well.
Tree Swallows will generally only lay one brood of eggs per season, although some pay attempt to lay a second brood if their first nest fails. This will only occur however if the first brood fails early in the breeding season. The female Tree Swallow generally lays 4-7 eggs and incubates them soley by herself, with no help from the male. The eggs will take approximately 14 days to hatch. The young will then take between 16-24 days before they fledge.
The Tree Swallow not only eats insects such as grasshoppers, crickets and beetles, but also makes a substantial use of vegetable foods like berries and seeds. They are the only species of swallow that incorporates such a large amount of vegetable foods into their diet.
sources:
http://www.birds.cornell.edu/BOW/TRESWA/
http://en.wikipedia.org/wiki/Tree_swallow
January 8th, 2008
www.4to40.com
A swallow builds its nest inside farm buildings and on ledges in old chimneys. The nest is made of mud, straw and saliva, with feathers and wool to line the inside. It takes a pair of swallows up to several weeks to make the saucer-shaped nest in the rafters of a barn. Swallows starts arriving in Europe at the end of March, a little earlier than their close relatives, the house martins.
They spend the winter in South Africa and usually return to the same district - and even the same nest - where they settled before. The female lays four or five eggs, white with reddish-brown speckles. She sits on them for about 15 days before they hatch out. Both parents then feed the nestlings with insects which they catch while flying. Swallows usually lay two sets of eggs.
They leave for their winter quarters in September, gathering in large flocks and often perching on telephone wires, before setting off. The young birds of the first brood leave before their parents and, by an inborn knowledge, know which way to go.
An old country proverb says: One swallow does not make a summer. This means that when the first one or two swallows arrive, summer has not yet come. It is not until large flocks are seen that countrymen know they can expect the warmer weather.
January 4th, 2008
www.longchuenbirdsnest.com
Ingredients:
113g birdās nest fibre, soaked until soft and stewed
113g long ā grain rice
1 salted duck egg
1 preserved duck egg
150 g shin of pork
salt
Method:
1.Wash and soak rice in water for 1 hour.
2. Shell preserved duck egg. Remove the dirt of salted duck egg and wash.
3. Wash, thickly slice, parboil and rinse shin of pork.
4. Put preserved duck egg and salted duck egg into 10 cups of water and bring to the boil. Add rice and shin of pork. Reduce to low heat and cook until congee is smooth. Remove preserved duck egg and salted duck egg and cut into wedges.
5.Add birdās nest to congee and cook for 5 minutes. Season with salt and combine with preserved duck egg, salted duck egg and Chinese parsley. Serve.
January 2nd, 2008
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