Saturday, 20 February 2010

Pigeons of Bristol 1: The Bleeding heart Doves and their relatives

One of the most important elements of Bristol’s bird collection is our range of pigeon and dove species. We currently hold thirteen different species, including the highly endangered Mauritius Pink pigeon. Most of the species we hold originate from south east Asia and Indonesia, so I will begin this series with a genus widely held in zoos and in private ownership, the Bleeding heart doves and their relatives.

Scattered across the islands of Indonesia, the Philippines and further out into the Pacific is a group of small terrestrial pigeons classed in the genus Gallicolumba (“Chicken-Pigeon”). Several species have a crimson blotch on their breast, which has given these species the English name of Bleeding Heart Doves (in fact, I have had visitors to the zoo reporting the birds we have as injured!). Not all species have this red patch however, and these tend to be termed Ground Doves instead.

About 20 species survive today, but several are threatened for the usual reasons of island endemic birds – introduced predators (especially rats and cats), and habitat destruction. All indications are that many more have become extinct without being recorded – the surviving species have a patchy distribution across the islands, with species present on two islands with none on intervening ones.

Bristol currently holds three species of Gallicolumba – The Luzon Bleeding Heart G.luzonica and the Mindanao Bleeding Heart G.criniger, plus the Sulawesi Quail Dove G.tristigmata. We are also working with a local organization in the Philippines which holds the only captive population of the Negros Bleeding Heart Dove G. keayi

The Luzon Bleeding heart
(see head of post for image)
Originating from the island of Luzon in the Philippines, the Luzon Bleeding Heart doves were one of the first of this genus to have captive populations established. Unfortunately, it was not realized at the time that G. luzonica has several different subspecies in different parts of the island, and the founders were drawn randomly from the different subspecies, so the captive population is not really usable for reintroduction purposes. They are however a very important model species for establishing proper husbandry and diet protocols, which have been used to good effect in the captive breeding programmes for the other species.

In the wild, luzonica is a very secretive bird of lowland forest, and is classed as Near Threatened on the IUCN Red List as a result of deforestation. It feeds on the forest floor on seeds, small fruits, and a high proportion of soil invertebrates, including snails. (Snails are an important food source for many birds, as they are a major source of calcium for females producing eggs).

Bristol zoo has produced the husbandry guidelines for luzonica and bred them annually since 1994 to the fifth generation. They are also fairly widely held by private keepers.

The Mindanao Bleeding Heart

As with luzonica, the Mindanao Bleeding heart is a very secretive and therefore under-reported bird. It is likely however that a substantial population decline has occurred in recent years. It inhabits primary and secondary forest below 750m, but since 1980 it has only been recorded from Rajah Sikatuna National Park on Bohol, Bislig on Mindanao and recent surveys in Mount Hamiguitan and Mount Hilong-hilong in eastern Mindanao. There has been near total loss of suitable habitat on Bohol, and on Mindanao remaining forest cover is estimated at only 29%. Illegal logging, trapping for both food and the internal Philippines wildlife trade are major threats.

Bristol Zoo has produced the husbandry guidelines for criniger, and has bred them annually since 1998 to the third generation.

Sulawesi Quail Dove

Lacking the red breast patch of the Bleeding Heart doves, the Sulawesi Quail dove is otherwise a typical Gallicolumba, feeding on the ground in forest areas. It is fairly common on Sulawesi, and unlike the Bleeding Heart doves is not considered threatened at present. It is somewhat larger than the Bleeding Heart doves, but is otherwise similar in diet.

Negros Bleeding Heart Dove

Not held at Bristol, but a conservation project we are involved in, the Negros Bleeding Heart is classed as Critically Endangered. It is found only on the islands of Negros and Panay in the Philippines, where probably only a few hundred individuals remain on each island. It appears to prefer dense closed-canopy forests below 1000m, although it tolerates secondary habitats on Panay where it has been recorded from selectively logged forest on limestone, and from open and severely degraded forest with few large trees. It seems unlikely that it undertakes more than very local movements in response to food patchiness. It has been recorded nesting in May and June with chicks fledging after only 12 days, apparently as an adaptation to the vulnerability of their open and low nests in epiphytic ferns.

Bristol Zoo is working with a local organization to establish a captive population using as founders birds rescued from the local wildlife trade. A few birds have been bred already, and the captive population currently stands at 18 birds. We are also working to protect the remaining forest cover on the islands, which is important for both the wildlife and the local people – forest catchments are important water sources and also provide fuel, and logging operations are a major threat to both.

To see a video of the Negros Bleeding heart dove in the wild look at the Arkive site here:

(images of Mindanao Bleeding heart from wikipedia, Sulawesi Quail dove from tolweb)

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