GALERIES : 206 espèces d'oiseaux. Toutes les images sont distibuées par l'agence NATURIMAGES.

MISE À JOUR DES GALERIES DU 01 MARS 2008 : plus de 160 nouvelles images de 20 espèces différentes ICI

Roselin cramoisi
Rougegorge familier
Rougequeue noir
Rousserolle effarvatte
Rousserolle turdoïde
Serin cini
Tourterelle des bois
Sarcelle d'été
Traquet oreillard
Sittelle torchepot
Sterne arctique
Sterne caugek
Sterne pierregarin
Tarier des prés
Tarin des aulnes
Torcol fourmilier
Tournepierre à collier
Tourterelle turque
Troglodyte mignon
Verdier d'Europe
blanc
Coucou gris et Pinson des arbres
Coucou gris et Hypolaïs polyglotte
blanc

ACTUALITÉ : image d'un martinet noir en vol en couverture de la revue NATURE du 26 avril 2007

nature-cover

Gliding birds continually change the shape and size of their wings, tuning performance by means of morphology. Aerodynamic theory predicts that birds should adjust wing sweep to suit glide speed and now a more refined aerodynamic model has been developed, based on wind-tunnel data. The results reveal a remarkable degree of control: swifts can halve sink speed or triple turning rate by choosing the most suitable sweep. Extended wings are used in slow glides and turns, swept wings for fast glides and (sacrificing lift for load bearing) in fast turns. The efficiency of 'morphing' wings is such that aircraft designers see them as possible successors to current variable-geometry wings: but the swift got there first. The stunning cover photo, by Jean-François Cornuet, shows a gliding swift in a tight turn. Taken at the swift's flight level, it shows how thin and straight the wings remain during a steady glide. Note also that the bird's head is kept horizontal to maintain a level image of its surroundings.etter: How swifts control their glide performance with morphing wings.
D. Lentink, U. K. Müller, E. J. Stamhuis, R. de Kat, W. van Gestel, L. L. M. Veldhuis, P. Henningsson, A. Hedenström, J. J. Videler & J. L. van Leeuwen.

Site de NATURE : http://www.nature.com

swift-gallery

Le site officiel du peintre et sculpteur Blasco MENTOR : http://blasco-mentor.fr

Contact : jfc@jfcornuet.info