Archived 2010-2011 topics: Helmeted Woodpecker (Dryocopus galeatus): downlist to Near Threatened?

Link to BirdLife species factsheet for Helmeted Woodpecker

Helmeted Woodpecker Dryocopus galeatus is currently listed as Vulnerable under criteria A2c; A3c; A4c on the basis that a population decline equivalent to 30-49% over 10 years was suspected in the past and is projected in the future, owing to widespread deforestation.

The currently suspected rate of decline may no longer be justified, as deforestation rates throughout the species’s range may have slowed and now perhaps average lower than 30% over 10 years (R. Clay in litt. 2007). Based on this observation, the inference of a lower rate of decline is probably justified, as deforestation and habitat degradation are nevertheless ongoing threats. However, improved knowledge of the species’s life history means that the rate of decline should be estimated for a period of 21 years (estimate of three generations).

The species may be eligible for downlisting to Near Threatened under the A criterion; however the rate of decline needs to be re-estimated. It has been noted that the species could potentially qualify for Vulnerable status under criterion C2a(i), on the basis that the declining population may number fewer than 10,000 mature individuals; however, the population is thought to number more than this, albeit not much more (R. Clay in litt. 2007).

Comments are invited on the proposed downlisting to Near Threatened and up-to-date information is requested on this species’s likely population size, the estimated rate of decline over 21 years and the severity of threats.

No related posts.

This entry was posted in Archive, South America and tagged . Bookmark the permalink.

5 Responses to Archived 2010-2011 topics: Helmeted Woodpecker (Dryocopus galeatus): downlist to Near Threatened?

  1. 1)I believe there is no possibility of reducing the threat category of Dryocopus galeatus from “Vulnerable” to “Near Threatened”.
    Although the rate of deforestation has decreased, the regions whose recent records of this species were made in Brazil, are represented by highly fragmented landscapes, with little or no connectivity between fragments, so that although there are reports of D. galeatus inhabiting forest fragments of small size and high degree of anthropogenic impacts, there is no long term studies showing the longevity of the permanence of this species in such locations. In the Location of Abelardo Luz, west of Santa Catarina state, southern Brazil, we’re following for nearly three years of a male D. galeatus found in a riparian fragment of more than 10 hectares (all of these areas are not protected) connected to a larger fragment of approximately 100 hectares since the start of monitoring there is no record of females or more than one male at the site, suggesting that the possibility of displacement of this species is low.

    2) I think it unlikely that the world population is 10,000 individuals, and in Brazil there is no study published regarding the status of this species in terms of population density within and outside of protected areas, so that any mention of this type data would be mere speculation.

    3) Likewise, lack of data on population dynamics of species in Brazil, or even a chronological tracking of the number of records for the species is not possible to assess, to the present, this type of information.

    4) In my opinion the greatest threats today are the mischaracterization of the species habitat (including the reduction of nesting sites) and loss of connectivity in the landscape.

    Remember that the majority of confirmed recent records for this species in Brazil have been outside of protected areas in any category.

    Cheers

    Glauco Kohler

  2. We find Dryocopus galeatus in degraded and fragmented forest, but it is much more numerous in mature forest, which is very rare now within its Atlantic forest range. One hypothesis is that in logged forest Dryocopus galeatus can´t compete well with other woodpeckers or other hole-nesting birds. So in my opinion total forest loss (as measured by remote sensing) is not a reliable way to estimate population declines. We also need to consider population declines provoked by reductions in habitat quality, where selective logging removes trees and changes the forest structure. I guess selective logging must affect more than half of the remaining Atlantic forest in Argentina.

  3. In my opinion, Dryocopus galeatus is declining. Even though there is not a large scale loss of Atlantic forest in Argentina today, there is a slow but permanent loss of forest and reduction in the quality of the forest, that I think affects Dryocopus galeatus. As Kristina mentioned, it could be because of competition with other birds. Also, just because there´s an adult doesn´t mean it is breeding every year. We have found a territory with a female, who seems to be alone now for more than a year, in a protected area.

    I think the global population is less than 10,000.

    In Paraguay deforestacion continues and the remaining fragments are in a very precarious situation (many of them could be eliminated at any time). In places like San Rafael, one of the largest fragments, this bird was scarce in the early 2000s; I don´t know about the current situation. Some of the places in Paraguay with important populations of Dryocopus galeatus, have already been totally or partially deforested (like Yaguarete Forest).

    Until we have a better idea of the interactions between D galeatus and other species of birds, I think we should leave it as Vulnerable at least, if not elevate it to Endangered.

    I´m interested to know the source of the informacion about its life history, that one generation is 7 years. Can anyone tell me the source?

  4. I agree with Glauco Kohler and Alejandro Bodrati who commented before me that the global population of Helmeted Woodpecker is likely less than 10.000 individuals. Chebez (2008) also questioned the BirdLife estimate of 10.000-20.000 individuals as overly optimistic. At the 2010 International Ornithological Congress (IOC) in Campos do Jordao we had a round-table discussion about conservation of Atlantic Forest birds with 40 participants including from Brazil, Paraguay and Argentina. The consensus was that despite a recent increase in known occupied sites and sightings in disturbed habitats, D. galeatus occurs mostly in or near mature and well-protected forests, and remains a rare species throughout its range. With Alejandro Bodrati and Raphael Santos I have an article in press in Neotropical Birding about Helmeted Woodpecker (Lammertink et al. in press). In it we comment on its global conservation status and conclude that is squarely belongs in the Vulnerable category.

    Global population estimate:
    BirdLife International (2010) estimates the global range of the Helmeted Woodpecker at 24,000 km2. If all of that was suitably forested habitat for the species, and if there was a global population of 10,000, it would mean there was one individual on every 2.4 km2 of habitat or one pair on every 4.8 km2. Those are densities seen only in Dryocopus species that are common and adapt well to modified forests, such as D. pileatus and D. martius. However D. galeatus by all accounts is a rare species that reaches is best numbers in old forest, even though it has been seen occasionally in fragments and modified forests in recent years. To illustrate the affinity of D. galeatus with old forest, Bodrati and Cockle (2006) in Misiones province, Argentina surveyed 20 sites with a wide variety of disturbance and fragmentation degrees. D. galeatus was rare at most sites but encounter rates were distinctively higher, with one record every few days, at two sites with primary forest. In an as yet unpublished study by Ernesto Krauczuk in southern Misiones, Helmeted Woodpecker was recorded in primary forest in 7 out of 46 days, but in only 1 out of 35 days in adjacent disturbed forest.

    Helmeted Woodpecker is often absent from large tracts of apparently suitable habitat (Collar et al. 1992). Two resident ornithologists in Iguazú (Argentina), Miguel Castelino and Daniel Somay, commented to me in 2008 that in Iguazú National Park (550 km2 of mature but not primary forest), D. galeatus is known from only 5 or 6 territories during the past 25 years, and these are not occupied continuously over time. Large portions of the park appear not or rarely used by the species based on intensive ornithological work. In Rio Negrinho county in Santa Catarina state, Brazil, Raphael Santos has been monitoring Helmeted Woodpecker for several years, but has found only one territory of the species in a tract of secondary forest of over 200 km2. These findings (one territory per 120 to 200 km2 of forest – note this is density, not territory size) may well be representative for much of the range of the species because nearly all remaining Atlantic Forest in the range of the bird is secondary. At such densities there would be 120 to 200 territories in the 24,000 km2 range that BirdLife estimated, or a global population of 300-500 individuals at an occupation of 2.5 birds per territory. Granted, in the few areas of old-growth forest or even in some contiguous well-protected secondary forest the species may reach higher densities (notably in some areas in Paraguay) and there may be more than 24,000 km2 of forest in the current range of the species, so there could be a population of around 1,000. But it is a stretch to arrive at a global population of over 10,000.

    Decline rate:
    I am unaware of any current estimates of rate of forest cover change in the range of the Helmeted Woodpecker over a 3-generation period. However even if such an estimate is available, the decline rate of this species would be underestimated by simply looking at decline rate of forest cover. There is good evidence that this species reaches its best numbers in old forest, as cited above. As Glauco and Alejandro indicate, there is a continuing decline of habitat quality in many remaining forest areas. The true rate of decline in this species is a combination of forest cover loss plus probable population decline in forested areas under exploitation.

    Fragmentation:
    From looking at forest cover maps, I agree with Glauco that the global population of the species is severely fragmented. It should not be considered as a single population.

    Martjan Lammertink

    References

    BirdLife International (2010) Species factsheet: Dryocopus galeatus. http://www.birdlife.org

    Bodrati, A. & Cockle, K. (2006) Habitat, distribution, and conservation of Atlantic Forest birds in Argentina: notes on nine rare or threatened species. Ornitol. Neotrop. 17: 243–258

    Chebez, J.C. (2008) Los Que Se Van. Aves. Tomo 2. Buenos Aires: Editorial Albatros

    Lammertink, M., Bodrati, A. and Santos, R. E. F. 2011. Helmeted Woodpecker (Dryocopus galeatus), a little known Atlantic Forest endemic. Neotropical Birding 8 (in press).

  5. Adrian Eisen Rupp says:

    In my opinion Dryocopus galeatus should not change categories. In Santa Catarina we have more records than in the past, but that’s because there are more ornithologists in the field. D galeatus is extinct in the region of Blumenau, probably because of the loss of quality of the forest, as Kristina mentioned. In REBIO Sassafras it was an uncommon species, mostly distributed in the northern half of the Valley of Itajai, and it was only recorded in stretches of good quality forest (old trees). In the west of Santa Catarina D galeatus suffered from fragmentation and the existing fragments are being degraded constantly, and forest recovery suffers because the ranchers release their cattle into the understory in winter. I do not think the global population is larger than 10,000!

    In the Chapeco region the species is losing habitat because of dams, which end up flooding the small forest remnants in the region. The Floresta Nacional de Chapeco has 1500 ha but only 1/3 is native forest, the rest is plantations of Pinus spp.

    Adrian Eisen Rupp

Comments are closed.