According to the International Union for Conservation of Nature and Natural Resources (IUCN), the world has 218 species of woodpeckers in the family Picidae: sapsuckers, flickers, woodpeckers, wrynecks, and piculets. Four are assessed as critically endangered, seven are vulnerable, fifteen are near threatened, and 192 are species of “least concern.” At first glace, the status of most of the woodpeckers is encouraging. A closer look however, paints a less positive picture.
Woodpecker Habitat is Declining Worldwide
Woodpeckers live on every continent except Australia and Antarctica wherever there are trees—but the types of forests they inhabit are dwindling, mostly due to forestry and conversion of woodland for farming, building, and road development. Woodpeckers rely on mature forests with both young and old trees, trees of various species and sizes including very large trees, and lots of dead wood. This environment provides them with food, shelter, and nesting sites. In addition, some species require very large areas of woodland to sustain their populations because they are solitary birds, widely dispersed.
The four critically endangered species are snapshots of what the majority of woodpecker species may soon face:
- The Imperial Woodpecker, Campephilus imperialis of Mexico may already be extinct. Although it was long hunted for food and medicinal purposes, it was the destruction of its habitat—large undisturbed areas of open pine forests—that finally decimated the population. This woodpecker has not been seen since 1956.
- The Ivory Billed Woodpecker, Campephilus principalis, once inhabited the old growth bottomlands of the southeastern United States and Cuba. If any now live, they are a tiny population surviving in isolated pockets that have not been logged or cleared for farming.
- The Okinawa Woodpecker, Dendrocopos noguchi, lives only on Okinawa Island in Japan. The subtropical forest with mature trees that it depends on now exists only at higher elevations, and a 1996 estimate of numbers found only about seventy-five breeding adults.
- Kaempfers Woodpecker, Celeus obrieni, was believed extinct until 1996 when the first sighting in eighty years was confirmed. Native to Brazil, the bird lost ground to building, agriculture, ranching, and road building. It may be more numerous than was once thought, but dispersed thinly over a large area.
The critically endangered species highlight the greatest threat to woodpeckers—people.
Why are Woodpeckers Vulnerable?
Scientists have identified characteristics of woodpeckers that make them particularly vulnerable to forest clearing:
- Many woodpecker species, particularly those that live at low elevations, have a very limited range. If logging destroys the entire range, they have nowhere else to go.
- Other species have a wide range but a very specialized food supply and individuals are widely dispersed. The population requires a large undisturbed area to sustain itself.
- Managed forests don’t support woodpeckers well: all the trees tend to be of similar ages, there are fewer varieties of tree species, and dead wood is in short supply.
Unfortunately the greatest variety of woodpecker species is found in the broadleaved forests of the tropics and subtropics where habitat destruction is at its worst.
Woodpeckers and Biodiversity
Woodpeckers are thought to be good indicators of biodiversity: the more woodpeckers, the more other bird species, and the more species of living things in general. In fact, some woodpeckers are considered to be keystone species—species upon which many other organisms depend. If keystone species die off, others fail as well:
- Nesting sites, excavated by woodpeckers and then abandoned after use, provide homes for other cavity nesting birds, reptiles, mammals etc.
- When woodpeckers tear apart rotting wood, they expose invertebrates—insects and their larvae, spiders, worms etc.—that other animals feed on.
- Woodpeckers play an important role in the disintegration and decay of dead wood.
- Because they forage and build nests in dead trees, woodpeckers may be important in the dispersal of fungi that break down wood.
- Woodpeckers help keep insect populations under control, especially those that damage wood.
Because abundant woodpeckers indicate high biodiversity and a healthy ecosystem, scientists are studying them as a means of identifying areas where conservation is particularly important.
The Future of Woodpeckers
The future of woodpeckers depends on humans not destroying the mature mixed forests that support them. Unfortunately, much of the research to date has focused on species of the temperate and boreal forests in the north, while woodpecker “hot spots” are in the tropics and subtropics. To even accurately assess whether they are in danger of sudden decline we need to know more about them.
Sources
The IUCN Red List of Threatened Species. International Union for Conservation of Nature and Natural Resources.
"Why Study Woodpeckers? The Significance of Woodpeckers in Forest Ecosystems." Virkkala, R. - Annales Zoologici Fennici 43: 82 – 85. 2006
“Woodpeckers : Distribution, Conservation, and Research in a Global Perspective.” Mikusinski, Grzegorz. Annales Zoologici Fennici 43: 86 -95. 2006.
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