The ivory woodpecker is a rare and elusive bird found in the old growth forests of the Pacific Northwest. With its striking black and white plumage and brilliant red crest, the ivory woodpecker has captivated ornithologists and birdwatchers for decades. However, due to habitat loss and fragmentation, the ivory woodpecker population has declined dramatically over the past century. Exact population numbers are difficult to determine for this shy bird that inhabits remote forest areas. But conservationists estimate there are likely only a few thousand ivory woodpeckers left in the wild.
Historic Ivory Woodpecker Population
The ivory woodpecker was once fairly widespread throughout the dense, old growth forests of Oregon, Washington, and British Columbia. Early ornithologists estimated the pre-logging population in the Pacific Northwest to be around 20,000 birds in the late 1800s. Large forest fires helped create optimal habitat conditions for the ivory woodpecker by opening up stands of over-mature forests. The ivory woodpecker thrived on recently burned forest areas with an abundance of dead and dying trees. This provided ample nesting and foraging opportunities for this specialized woodpecker that feeds almost exclusively on wood-boring beetle larvae found under charred bark.
But in the early 20th century, extensive logging operations began removing the crucial old growth forest habitat required by the ivory woodpecker. Clear cut logging was most intensive between the 1950s and 1980s. Vast swaths of primeval forest were leveled and replaced with second growth stands unsuitable for the ivory woodpecker. Populations plummeted as a result. One 1988 study estimated that 98% of the bird’s nesting habitat had been logged since the 1800s. From a peak historic population estimated at 20,000, ivory woodpecker numbers dropped to around 2,000 birds by the 1990s according to expert surveys.
Current Population
Today, researchers estimate the total population of ivory woodpeckers is likely between 2,500 to 3,000 individuals. They inhabit pockets of remaining old growth and mature forests across Oregon, Washington, and British Columbia. Their estimated range covers about 15,000 square miles of forestland.
Population estimates are approximate because the ivory woodpecker occupies such a vast, isolated range. Researchers conduct extensive surveys and sound-mapping of breeding pairs, and then extrapolate total numbers based on available habitat. These surveys indicate the birds persist at low densities even in optimal habitat. Breeding pairs may range across one to three square miles of forest. But only 10-15% of this range is actually used on a regular basis.
Location | Estimated Population |
---|---|
Oregon | 1,000 – 1,500 |
Washington | 850 – 1,200 |
British Columbia | 600 – 900 |
These estimates are based on intensive monitoring of known nesting sites and projections across suitable habitat. Overall, biologists believe the total ivory woodpecker population has stabilized over the past decade thanks to expanded protected areas. However, their small numbers and isolation into fragmented habitats means the species remains vulnerable to extinction.
Threats to Ivory Woodpeckers
There are several ongoing threats contributing to the tenuous status of the ivory woodpecker:
Habitat Loss
The primary threat facing ivory woodpeckers is continued loss of nesting and foraging habitat. While clear cut logging has slowed from its peak, some old growth forests continue to be logged. Forest fires are also suppressed more quickly now, reducing the burned forest patches preferred by ivory woodpeckers.
Fragmented Habitats
Existing habitats have become fragmented into smaller, isolated patches surrounded by younger forests or development. This makes it harder for breeding pairs to find each other and reduces genetic diversity. Fragmented habitats also provide less protection from predators.
Insecticide Use
The widespread aerial spraying of insecticides to control forest pests has reduced the woodpecker’s food supply. The chemicals can kill off the wood-boring beetle larvae that are the ivory woodpecker’s primary prey.
Climate Change
Climate change poses a long-term threat by increasing severe weather, altering forest composition, and enabling infestations of pests and disease. Drought conditions also increase risk of devastating forest fires occurring more frequently.
Nest Predation
Nest predation by animals such as squirrels, ravens, and martens limits reproduction. Fragmented habitats make nests more accessible to predators.
Conservation Efforts
While challenges remain, there are some encouraging conservation developments that may help stabilize ivory woodpecker populations:
- Over 6 million acres of additional old growth forests were protected in the Pacific Northwest in the 1990s and 2000s. This helps preserve nesting habitat.
- Restrictions were placed on aerial insecticide spraying over 24 million acres of forest.
- Nonprofit groups have helped fund research and surveys of ivory woodpecker populations.
- Selective thinning and prescribed burns are used to mimic natural conditions in some protected areas.
- Artificial nest sites have been installed to boost breeding success.
Continued conservation efforts focused on preserving remaining old growth forests will be crucial for the ivory woodpecker’s survival. While still a vulnerable species, there is hope that strengthened protections and habitat management can gradually restore ivory woodpecker populations.
Conclusion
The ivory woodpecker has declined dramatically from its historic numbers due to extensive old growth forest loss. Current population estimates place the total at 2,500-3,000 individuals, inhabiting fragmented pockets of remaining habitat across Oregon, Washington and British Columbia. While strengthened conservation measures have helped stabilize numbers, the ivory woodpecker remains vulnerable. Continued protection of old growth forests remains vital for the future of this iconic bird of the Pacific Northwest.