Busard tacheté
Circus assimilis
Rapace de taille moyenne à longues pattes, aux ailes longues et étroites. L'adulte a les parties inférieures châtain avec des taches blanches frappantes ; l'immature est strié dessous. Il vole bas à faible vitesse au-dessus des habitats ouverts. Se perche souvent sur les poteaux de clôture. Se trouve dans des habitats plus secs que le Busard des roseaux.
Identification
The spotted harrier is a medium-sized, slender bird of prey with adult females reaching 58–61 cm. Both adults and juvenile birds have an owl-like facial ruff that creates the appearance of a short, broad head as well as long yellow legs. The spotted harrier's wings feature prominent black tips and the tail is prominently barred and slightly wedge shaped.<p>Adult males are much smaller than the females only growing to 50–55 cm. Adult birds have blue to grey upper parts with a chestnut face and underparts that feature numerous white spots. Juvenile birds in their first year of life are mostly a dark brown and buff on their upperparts with pale buff underparts that feature brown streaks across the chest and stomach. During the second year of their life the spotted harrier takes on almost adult colouring with white streaks across their underparts instead of the prominent spots that can be seen on adults.
Taxonomie
The spotted harrier belongs to the family Accipitridae. Accipitridae is the largest family in the order Accipitriformes and encompasses many of the diurnal birds of prey including hawks and eagles. It is one of the largest avian families with 233 species in 67 genera included in the family worldwide.
- Nom scientifique
- Circus assimilis
- Autorité
- Jardine & Selby, 1828
- Ordre
- Accipitriformes
- Famille
- Accipitridés
- Genre
- Circaète
Répartition et habitat
The spotted harrier is native to Australia and Indonesia, however vagrant populations have been seen in Timor-Leste. It has a geographic range of more than 20,000km2 (Birdlife International, 2012). Spotted harriers can be seen throughout most of Australia's mainland, except in densely forested or woodland habitats of the coast, escarpments and ranges, and rarely in Tasmania. In NSW individuals are widely dispersed, comprising a single population.<p>The spotted harrier is a terrestrial bird residing in open grasslands, open woodland including acacia and mallee, inland riparian woodland, grassland and shrubland. It can be most commonly found in native grassland however it is also seen in agricultural land and inland wetlands for the purpose of foraging.
- Migration
- Nomadic movement
Conservation
Due to its extremely large range, and its large and stable population, the spotted harrier has been designated as a species of least concern by the International Union for Conservation of Nature.<p>The species was included in a NSW population survey in 1977-81 which used 75 one degree grids to find bird population numbers. The spotted harrier recorded at mostly moderate to high reporting rates (11-40% and more than 40% of surveys per grid, respectively). Breeding was recorded in 14 of these grids. A repeat of this survey was performed in 1998-2002 which found that spotted harrier numbers had declined (less than 20% of surveys per grid), with breeding in only 6 grids. This suggests that a statewide decline of 70% over 3 generations (30 years) will occur. One issue with this study is that due to the large distribution of the spotted harrier this study only covers a small sample of the entire species, misrepresenting the species as a whole. Also it is known that there are many threatening processes occurring in NSW that are affecting populations on a large scale basis that are not happening as prolifically in other areas. This study should be performed through the whole distribution of the species to find and accurate summary of the species population status. This study does however accurately represent populations in NSW and therefore a management plan can be put in place to manage numbers in this state alone.
- Tendance de la population
- stable
Photos
Distribution
Autres Oiseaux
Bergeronnette du Cap
Motacilla capensis
Oiseau élégant à longue queue avec un dos brunâtre, des dessous pâles et une bande pectorale noire. Les rectrices externes blanches sont bien visibles en vol. On le trouve dans la plupart des habitats ouverts, surtout près de l'eau. Se nourrit en marchant sur le sol, balançant constamment sa queue. Le cri est un « tseeei » bourdonnant qui est souvent doublé. Le chant est un mélange complexe de différentes notes répétées. Similaire à la Bergeronnette des montagnes mais a le dessus brun plutôt que gris, et la Bergeronnette du Cap a moins de blanc dans les ailes et la queue. Également similaire à la Bergeronnette pie africaine juvénile mais n'a pas de panneau blanc sur l'aile.
Niltava vif
Niltava oatesi
Gobe-mouches robuste et migrateur des forêts denses. Il se reproduit en montagne et hiverne à plus basse altitude. Le mâle est bleu-noirâtre dessus et roux dessous avec une calotte, un collier, des épaules et une queue bleu profond. La femelle est brun terne, avec des parties inférieures brun plus pâle et une gorge chamois. Comme les autres Niltavas, il fourrage principalement à des niveaux moyens, souvent avec d'autres espèces. Similaire aux Niltavas à ventre roux et aux Niltavas du Fujian, mais le mâle a une encoche rousse dans la gorge sombre et la femelle n'a pas de croissant bleu sur le cou ni de bande blanche sur la gorge. Son chant est une série de sifflements clairs et ondulants, parfois mêlés de courts trilles.
Tityra à couronne noire
Tityra inquisitor
Bel oiseau gris argenté des forêts tropicales humides de plaine et des zones semi-ouvertes adjacentes avec des arbres plus hauts. Généralement trouvé aux niveaux moyens-supérieurs des arbres fruitiers, parfois en petits groupes qui se mêlent facilement au Tityra masqué plus commun. Le Tityra couronné se distingue du Tityra masqué légèrement plus grand par son bec entièrement noir. Le mâle est plus argenté dans l'ensemble, avec une calotte noire ; la femelle a une face brune et une calotte noire plus petite. Les tityras nichent dans des cavités d'arbres, qu'ils volent parfois aux pics.
Commencez votre Voyage d'Observation d'Oiseaux
Identifiez les oiseaux dehors et gardez le guide à portée de main pour votre prochaine observation.