Tags

, , , , , , , , ,

Endangered Species series main post.

Birds first appeared during the Late Jurassic, arising from amongst the therapod dinosaurs; the infamous Archaeopteryx has been dated to c 150-145 mya. Modern birds are, by and large, much more accomplished fliers than the early avians and have evolved to fit all manner of ecological niches. There are around 9,000 known species. Representatives can be found all around the world, enriching our lives as they go about the messy business of living. Birds are generally defined by several characteristics: a toothless beak; feathers (that many dinosaurs are known to also have feathers has raised etymological issues); high metabolism; hard-shelled eggs; lightweight, robust skeleton. As birds are so varied in distribution and form, they are threatened by a great many natural and anthropogenic factors. This might seem to be counterintuitive; surely an organism capable of flight can escape such pressures. For some species, this is possible. Others are less capable of responding to limiting factors and thus exhibit similar responses to threats as do other taxa.

[1] Waggoner, B., JRH (1996). Introduction to the Aves. University of California at Berkeley. [online]
[2] Tudge, C. (2009). The Secret Life of Birds. Penguin. [available to buy]

Campbell Islands Teal (Anas nesiotis)

A. nesiotis is a nocturnal local endemic of Dent Island, New Zealand. The species was first described in 1886 but was not collected from Dent Island until 1975. In 1990, the breeding population was estimated at 60-100 birds, which declined further to 25 pairs in 1998. The species has been successfully introduced to Codfish and Campbell Islands. The total population is now estimated to be around 200 birds, though this includes captive specimens. Alien species, severe weather and avian diseases are primary threats.

[1] Birdlife International (2010). Anas nesiotis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Anas nesiotis. [online]

Black-breasted Puffleg (Eriocnemis nigrivestis)

The attractively named black-breasted puffleg is a hummingbird endemic to Ecuador where it inhabits the north-western slopes of the Volcan Pichincha and the Cordillera de Toisan. The Pinchincha population numbers approximately 160 individuals and is restricted to an area of around 34km2. The total wild population has been estimated at between 250 and 999 individuals. Deforestation and habitat destruction is the greatest cause of past decline and the greatest ongoing threat to the species.

[1] Birdlife International (2010). Eriocnemis nigrivestis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Eriocnemis nigrivestis.  [online]
Image © Benjamin Schwartz

Enigmatic Owlet-nightjar (Aegotheles savesi)

Sighted only once since 1960, A. savesi is endemic to New Caledonia where it likely exists as a tiny and spatially restricted population. Little is known of the species, even amongst local people. It is thought that it exploits a more terrestrial lifestyle than that of other Aegotheles species. Based on a similar species – A. cristatus – it is thought that introduced predators and habitat loss are primary threats.

[1] Birdlife International (2010). Aegotheles savesi. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Aegotheles savesi. [online]

Bengal Florican (Houbaropsis bengalensis)

The Bengal florican is a bustard – the Family Otididae which includes the heaviest flying bird, the great bustard (Otis tarda) – which occurs in two populations; one in India, through Nepal, the other in southeast Asia. These populations fragmented into small sub-populations. The total global population is thought to be between 250 and 999 individuals. There have been no recent surveys of the Indian population. The primary threat is loss of key grassland habitat.

[1] Birdlife International (2010). Houbaropsis bengalensis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Houbaropsis bengalensis. [online]

Blue-throated Macaw (Ara glaucogularis)

A much loved staple of the pet trade, the blue-throated macaw saw its population decimated in three generations. The remaining wild population – estimated at around 250-300 individuals – is found in Llanos de Mojos, Bolivia. Drastic reduction of the trade in wild-caught birds has halted the decline and there are signs of recovery. Other threats are hunting for feathers and meat, inter-specific competition and inbreeding of fragmented sub-populations.

[1] Birdlife International (2010). Ara glaucogularis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Ara glaucogularis. [online]
Image © Jeff Kubina

Masafuera Rayadito (Aphrastura masafuerae)

The Masafuera Rayadito is a member of the ovenbird family (Furnariidae), a family famous for the horneros (Furnarius spp.) which build oven-like clay nests. The Rayadito is more demure, nesting in natural cavities. It is found only on the island of Alejandro Selkirk in the Juan Fernandez Islands, Chile. Recent surveys put the population at c. 248 birds though based on availability of suitable habitat, the total population may number as many as 1,000. Primary threats are habitat loss, climate change and an increase in red-backed hawks (Buteo polysoma exsul).

[1] Birdlife International (2010). Aphrastura masafuerae. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Aphrastura masafuerae [online]

São Tomé/Dwarf Olive Ibis (Bostrychia bocagei)

First sighted in 1990, this species was long considered a subspecies of the larger olive ibis (Bostrychia olivacea). It is endemic to São Tomé, São Tomé e Príncipe where it inhabits catchments in the south-west and centre of the island. Threatened by habitat loss and intense hunting pressure, the population has dwindled to fewer than 50 birds.

[1] Birdlife International (2010). Bostrychia bocagei. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Bostrychia bocagei [online]
Image © Christian Hinzen

Réunion Cuckoo-shrike (Coracina newtoni)

Neither a cuckoo nor a shrike, C. newtoni can be found in two small patches of forest to the north of the island of Reunion in the Indian Ocean. One of these sub-populations now consists of fewer than 25 individuals. From 2003 to 2007, numbers of unpaired males increased by over 10% every year, indicative of a heavy male skew in the population. Predation by rats, disturbance, invasive plants and inter-specific competition continue to contribute to the decline of the species. Fewer than 25 breeding pairs remained as of 2007.

[1] Birdlife International (2010). Coracina newtoni. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Coracina newtoni. [online]
Image © Jean-Michel Probst

Kaempfer’s Woodpecker (Celeus obrieni)

Since collection of the type specimen in 1926, this Brazilian woodpecker was thought extinct for several decades. However, a male was caught in a mist net in 2006; several specimens have been recorded since. It is known from several states where it is thought to be associated with bamboo and babassu palm forest. The current population is cautiously estimated at 50-250 individuals. Due to the number of captures and the likely size of its range, however, it is likely that the population is large and the species may soon be downlisted.

[1] Birdlife International (2010). Celeus obrieni. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Celeus obrieni.  [online]
Image © Ciro Albano

Ridgway’s Hawk (Buteo ridgwayi)

Thos familiar with bird taxonomy will notice that the common name of this species is a misnomer. Rather than being a true hawk (Accipiter spp.), Ridgeway’s is in fact a buzzard (Buteo spp.). Once recorded from Haiti and many associated islands, the species is now likely restricted to Los Haitises National Park in the Dominican Republic. The species is undergoing an annual decline of c. 5-10% of breeding pairs at one site which also experiences 10-15% annual forest loss. There were estimated to be between 80 and 120 breeding pairs as of 2006. A translocation effort by the Peregrine Fund is ongoing.

[1] Birdlife International (2010). Buteo ridgwayi. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Buteo ridgwayi. [online]

Black Stilt/Kakī (Himantopus novaezelandiae)

This species has been subjecty to intensive management efforts since 1981 when the population was just 23 individuals. Despite contstant effort, the species remains one of the rarest shorebirds in the world. The wild population has almost certainly been saved from extinction by the annual release of large numbers of captive-bred birds. Once widespread across North and South islands of New Zealand, breeding is now restricted to the Waitaki Valley on South Island. The total population stood at 78 birds as of 2007-08, 20 of which were breeding pairs. Predators, nest-site disturbance and stochastic weather events are the primary threats.

[1] BirdLife International (2009). Himantopus novaezelandiae. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] BirdLife International (2009). Himantopus novaezelandiae.  [online]
Image © Yang Zhang

White-chested White-eye (Zosterops albogularis)

Looking much like a colourful warbler, Z. albogularis inhabits Norfolk Island where the remnant population is confined to Norfolk Island National Park. Despite occasional reported sightings, official surveys have been unable to find a single individual. If the species persists, it does so in low numbers. It is threatened by rat predation and the destruction and alteration of suitable habitat.

[1] Birdlife International (2010). Zosterops albogularis. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Zosterops albogularis. [online]

Beck’s Petrel (Pseudobulweria becki)

Recently rediscovered (2007-08), Beck’s petrel is generally found along the island chain which includes Papua New Guinea and the Solomon Islands. The extent of its breeding range or area of occupancy whilst at sea are unknown. The global population is thought to be larger than originally estimated due to the sighting of around 160 birds between New Britain and New Ireland in 2008. The species may be threatened at its breeding grounds by invasive predators.

[1] Birdlife International (2010). Pseudobulweria becki. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Pseudobulweria becki. [online]
Image © Hadoram Shirihai

Raso Lark (Alauda razae)

As its common name attests, A. razae is found only on the islet of Raso (7km2) in the Cape Verde Islands. The species’ population appears to fluctuate in response to climactic conditions with recorded numbers veering from a low of 20-50 pairs to around 250 individuals. The species is especially vulnerable during periods of low abundance as the sex ratio becomes skewed 3:1 towards males. Primary threats are grought and nest predation.

[1] Birdlife International (2010). Alauda razae. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
[2] Birdlife International (2010). Alauda razae. [online]
About these ads