New research has shown that Europe’s farmland birds have declined by almost 50% in the past 25 years – a trend caused by EU-wide agricultural intensification being driven by a policy in need of urgent reform. The results, released on the 7th June, bring together the most comprehensive biodiversity indicators of their kind in Europe, collated by the Pan-European Common Bird Monitoring Scheme (PECBMS). The data, collected from 20 national breeding bird surveys spanning Europe over the last 25 years, confirm the extent to which farmland birds have suffered. Across Europe as a whole from 1980 to 2005, common farmland birds have on average fallen in number by 44% – the most severe decline of the bird categories monitored (BirdLife 07.06.2007).

There will be (at least) two presentations on columbids at the IV International Symposium On Breeding Birds In Captivity, which is running from September 12th-16th, 2007 in Toronto, Canada:

Gary Michael (Louisville Zoo, Kentucky, USA)
Propagating the White-throated Ground Dove Gallicolumba xanthonura: world's first captive breeding and the establishment of an avicultural program

Apolinario Cariño, Angelita Cadeliña, Jose Baldado, Charlie Fabre, Emilia Lastica, Pavel Hospodarsky & Rene Vendiola (Mt. Talinis Peoples Organization Federation Inc., Dumaguete City, Philippines)
Conservation of the Critically Endangered Negros Bleeding-heart Pigeon on the Island of Negros, Philippines

Visit www.isbbc.org for further details.

There is increasing evidence that pathogens can play a significant role in species decline; and recent research has revealed the cost of blood parasitism to the endangered Pink Pigeon Columba mayeri. Scientists investigated the prevalence and effect of infection of the blood parasite, Leucocytozoon marchouxi, in the free-living Pink Pigeon population. Overall, L. marchouxi infection prevalence detected was 18·3%. Juveniles were more likely to be infected than older birds and there was geographical variation in infection prevalence. Survival of birds infected with L. marchouxi was lower than that of uninfected birds to 90 days post-sampling. This study suggests that while common haematozoa are well tolerated in healthy adults, these parasites may have greater pathogenic potential in susceptible juveniles.

Bunbury, N. (n.bunbury "at" uea.ac.uk), Barton, E., Jones, C. G., Greenwood, A.G., Tyler, K.M. and Bell, D.J. (2007). Avian blood parasites in an endangered columbid: Leucocytozoon marchouxi in the Mauritian Pink Pigeon Columba mayeri. Parasitology 134(6): 797-804.

The latest evaluation of the world’s birds has revealed that more species than ever are threatened with extinction. BirdLife International’s annual Red List update states that in 2007 an additional 12 species are now considered threatened with extinction (1221 in total) and an additional 17 species are now considered Near Threatened (812 in total). Therefore, 2033 species are urgent priorities for conservation action. The overall conservation status of the world’s birds has deteriorated steadily since 1988, when they were first comprehensively assessed with now more than a fifth (22%) of the planet’s birds is at increased risk of extinction. The threat status of two species of pigeon changed in this years’ revisions; the Mindanao Bleeding-heart Gallicolumba crinigera was down-listed to Vulnerable and Tawi-tawi Brown Dove Phapitreron cinereiceps was down-listed to Endangered (BirdLife 21.05.2007).

Mourning Dove Zenaida macroura call-count surveys in Mississippi, USA, suggest declining populations. Scientists have used available Mourning Dove call-count data to evaluate long-term Mourning Dove habitat relationships. Percent agriculture was positively correlated with relative dove abundance. Results suggest that observed localized declines in Mourning Dove abundance in Mississippi may be related to the conversion of agricultural lands to pine plantations. During the last 20 years, Mississippi lost more than 800,000 ha of cropland while forest cover represented largely by pine Pinus taeda plantations increased by more than 364,000 ha.

Elmore, R.D., Vilella (fvilella “at” cfr.msstate.edu), F.J. and Gerard, P.D. (2007). Landscape correlates along Mourning Dove call-count routes in Mississippi. Journal of Wildlife Management 71(2): 422–427.

The Common Ground Dove Columbina passerina and Plain-Breasted Ground Dove Columbina minuta are two Neotropical species of Ground Doves with similar morphology, behaviour and natural history; however, exhibit notably different distributions on Caribbean islands. While the Common Ground Dove (pictured) is found on a majority of them, the Plain-Breasted Ground Dove is restricted in the Caribbean to Trinidad. Scientists in Venezuela hypothesized that an explanation for this extreme difference in ranges was due to differences in at least three traits often associated with successful island colonization: morphological structures that promote long flight efficiency, dietary plasticity and water requirements. They tested the first factor by comparing several wing measurements and the other two factors with experiments on wild-caught birds in controlled conditions - but did not find significant differences in wing measures. The Common Ground Dove did show greater dietary plasticity, a wider diet breadth and lower daily water requirements than Plain-Breasted Ground Dove. Although colonization success is likely to be shaped by many variables, the success of Common Ground Dove in maintaining populations on so many Caribbean islands is at least partially explained by its ability to survive in environments with unpredictable food changes and severe fresh water limitations as usually found on some Caribbean islands.

del Mar Weisz, M. (marweisz328 “at” hotmail.com), Pérez, E.M. and Bulla, L. (2007). Why does the Common Ground Dove (Columbina passerina) colonize Caribbean islands but the Plain-Breasted Ground Dove (C. minuta) does not? Studies on Neotropical Fauna and Environment 42(2): 101–108.

One of the most important books to cover bird conservation in Ecuador and Peru, Biodiversity and Conservation in Tumbesian Ecuador and Peru, has been re-launched online. The Tumbesian region, which stretches from northern coastal Ecuador south to just north of Lima in Peru, holds exceptional numbers of endemic bird species including two species of dove, the Ochre-bellied Dove Leptotila ochraceiventris Ecuadorian Ground-dove Columbina buckleyi. The new version incorporates information has become available on sites and species since the book was originally published in 1995.

Biodiversity and Conservation in Tumbesian Ecuador and Peru is available for free download – see BirdLife (09-05-2007).

The Grenadian government has passed an amendment to the Grenada National Parks and Protected Areas Act, giving the Governor General the right to sell national parks land (and other protected areas) to private developers. This allows the sale of the Mount Hartman National Park, the last stronghold of the Critically Endangered Grenada Dove Leptotila wellsi, for a massive hotel and villa complex. Conservationists have also expressed concern over recent claims from the Grenadian government that the developer responsible for the proposed Four Seasons development has been given time to undertake a full Environmental Impact Assessment, and that “no final decision on the development has yet been made” on the hotel development. Photographic evidence suggests otherwise. Approximately half of Hog Island, a critical part of the Four Seasons project, has been cleared ready for building work to commence (BirdLife 08-05-2007).

The Cyprus government permitted the shooting of European Turtle Dove Streptopelia turtur this spring in certain coastal areas on Sunday May 6th and Wednesday May 9th despite spring hunting being prohibited by EU law and the European Turtle Dove being a species declining across Europe (BirdLife 04-05-2007).

The 25 protected areas within the Colombian Andean mountain range cover ~3.5 million hectares but not all ecosystems are adequately represented. Recent research by the Wildlife Conservation Society has shown the representation of bird species in these protected areas is relatively high but important gaps still exist - in particular relating to lower elevations and threatened species. Twenty-five of the 152 species classified in a threat category in Colombia have no populations in protected areas. The Endangered Tolima Dove Leptotila conoveri is one of such species. The situation is particularly critical for this species as most of the original vegetation cover in this region has already been destroyed.

Franco, P. (padufranco “at” telesat.com.co), Saavedra-Rodríguez, C.A. and Kattan, G.H. (2007) Bird species diversity captured by protected areas in the Andes of Colombia: a gap analysis. Oryx 41(1): 57-63.

On the Indonesian island of Sulawesi an assemblage of 11 pigeon species was found to be highly fruit dependent (96-100% of diets; significantly more so than hornbills, parrots and passerines); however, there was considerable variability in the diet breadths of these pigeon – the species with the greatest diet breath was 71% broader than the species with the most restricted diet breadth. Fig fruits were of outstanding importance to pigeons, contributing an average of ~59% of fruit in the monthly diets of pigeons during the 10 month study and therefore not simply a keystone food resource. The survival of fig populations is limited by a (1) that viable populations of figs can require huge areas; (2) fig reproduction is negatively affected by habitat fragmentation and drought; and (3) that the large trees on which strangler figs disproportionately occur are themselves rare and at increased risk of mortality in fragmented landscapes. The islands’ remaining unprotected forests are likely to have an important role in supporting viable fig and frugivorous pigeon populations.

Walker, J.S. (jon “at” columbidae.org.uk) (2007). Dietary specialization and fruit availability among frugivorous birds on Sulawesi. Ibis 149: 345-356.

The results of a study that examined the range expansions of temperate northern hemisphere Birds in Northern America has identified a significant shift northward (2.35 km/year) but no southward expansion – indicating a connection with global climate change. These results are similar to that observed in previous work conducted in Great Britain. Only one of the two pigeon species in the study displayed a significant northward expansion. The Inca dove Columbina inca has moved on average ~254 km north over a 26 year period up until 2002; the northward range limit of the Common Ground-dove Columbina passerine has not changed significantly.

Hitch, A.T. (hitchat “at” auburn.edu) and Leberg, P.L (2007). Breeding distributions of North American bird species moving north as a result of climate change. Conservation Biology 21(2): 534–539.

Volcanic eruptions are an important and natural source of catastrophic disturbance to ecological communities. The effects of the eruption of the Soufrière Hills volcano on the forest bird community of the Lesser Antillean island of Montserrat were monitored data from 1997 to 2005. Counts of most species were substantially lower following major ashfalls; however, this effect was short-lived, with rapid population recovery in subsequent years. Furthermore, levels of seasonal rainfall appear to have been at least as important in determining population trends as ashfall. Both pigeons included in the study, Scaly-naped Pigeon Columba squamosa and Bridled Quail-dove Geotrygon mystace, showed strong and significant declines in response to ‘Recent ashfall’ indicating population declines and/or redistributions away from ashfalls. Rainfall in the previous year also had a strong impact on the counts of both species, with both species responding positively to high wet-season rainfall, by increasing in abundance in the subsequent year.

Dalsgaard, B., Hilton, G.M. (geoff.hilton “at” rspb.org.uk), Gray, G.A.L., Aymer, L., Boatswain, J. and Daley, J. (2007). Impacts of a volcanic eruption on the forest bird community of Montserrat, Lesser Antilles. Ibis 149: 298–312.

A study examining the effects of edge, fragment size and isolation on bird species richness in southwestern Nigeria has found isolation, but not forest fragment size, is an important predictor of avian species richness in the highly fragmented and relatively small remnant forest patches in West Africa. None of the four pigeon species included in the study African Green Pigeon Treron calva, Tambourine Dove Turtur tympanistra, Blue-spotted Wood Dove Turtur afer or Red-eyed Dove Streptopelia semitorquata were not found to be negatively affected by fragmentation (fragment size or isolation); however, numbers of Red-eyed Dove declined nearer forest edges (Image: Blue-spotted Wood Dove).

Manu, S., Peach, W. and Cresswell, W. (wrlc "at" st-and.ac.uk) (2007). The effects of edge, fragment size and degree of isolation on avian species richness in highly fragmented forest in West Africa. Ibis 149: 287–297.

Malta’s spring hunting season of birds began on 10th April despite ongoing legal and political action taken by the European Commission. Since joining the EU in 2004, Malta has breached the European Birds Directive every year by allowing spring hunting of European Turtle-dove Streptopelia turtur and Common Quail Coturnix coturnix as Spring hunting is prohibited by the Birds Directive in order to protect wild birds during their migration from Africa to breeding grounds in Europe. Legal action by the European Commission against Malta began in June 2006, with a European Court case expected to start later this year. On 15 March 2007 the European Parliament adopted a strong resolution calling on Malta to end spring hunting and trapping of birds immediately. Malta’s spring hunting season will end on the 20 May (BirdLife 10-04-2007).

Following a major change in Indonesia’s forestry law, a ground-breaking initiative to protect and restore an area of Sumatra’s remaining dry lowland rainforest has now been made possible. The Harapan Rainforest Initiative will establish Indonesia’s first “forest ecosystem restoration concession” for the conservation and regeneration of a 101,000 hectares forest block in the lowlands of Sumatra. The change in law effectively allows for the first time, ‘production forest’ to be allocated for conservation and restoration. The area will become a refuge for many of Sumatra’s threatened birds will benefit the Large Green Pigeon Treron capelli, which is currently listed as Vulnerable (BirdLife 02-04-2007).