Hunting Season for White Pelicans?
American White Pelicans, Bear River Migratory Bird Refuge, Box Elder County, Utah 2002 © Rosalie Winard
For the past week, I’ve felt like a detective in the world of wildlife management perusing a 62-page report issued by the Idaho Department of Fish and Game (IDFG)--the 2009 Draft Pelican Management Plan. Both native American white pelicans and native Yellowstone cutthroat trout are listed as “species of greatest conservation need” in the Idaho Comprehensive Wildlife Conservation Strategy – but now it seems we may have to choose between bird and fish.
There’s concern in Idaho that breeding American white pelicans are increasingly foraging on native cutthroat trout populations in the southeastern part of the state – particularly the Blackfoot Reservoir, an anglers’ paradise. Although it’s stocked primarily with rainbow trout, a nonnative species (560,000 stocked in 2003), native cutthroat trout also spawn there. But their numbers have declined precipitously: From 4,700 spawning cutthroat trout documented there in 2001, the population dropped to just 14 in 2005, before rebounding to 208 in 2008.
IDFG’s analysis is that the white pelicans are responsible for the cutthroat’s decline and proposes to cut the number of nesting pelicans at the Blackfoot Reservoir by 50 percent or more. This means that a population that was recorded to be 2400 in 2008 would be reduced, over five years, to an average population of 700 breeding pelicans. The most drastic measure proposed to accomplish this is to create a hunting season for white pelicans.
In the early 1900s the Western population of white pelicans was 60,000 breeding birds in 24 breeding colonies. Now there are 13-15 breeding colonies and 46,000 breeding birds -- and Idaho supports 16% of those.
The key problem involves reservoir levels at the time when cutthoat trout need to migrate upstream to spawn. Low water levels make the run too shallow and too long – and too easy for pelicans to prey on the migrating trout. IDFG’s analysis is that the white pelicans are confined to taking fish only in the top 1-2 feet of water -- which means the trout are relatively safe from pelican predation if the water is deeper. Because irrigation for agricultural interests determines the water levels in Idaho’s reservoirs, however, the Idaho Fish and Game is unable to maintain adequate water for spawning trout in the Blackfoot River and Reservoir..
Aside from the relationship between low water levels and predation, the IDFG did not analyze any other factors that might be affecting cutthroat trout. “Fish and Game appears to be focusing on one specific factor, predation, instead of a more ecologically based approach that addresses additional contributing factors, including habitat,” wrote John Robinson, Public Lands Director of the Idaho Conservation League in a letter to IDFG regarding the plan. "In addition, no information is provided on water quality, nutrient levels, or impacts from recreation on fish and wildlife," he noted.
For example, a recent study by scientists at Idaho State University shows that remaining Yellowstone cutthroat trout populations face a high risk of decline due to high concentrations of selenium, an airborne trace mineral. The mineral’s presence has already essentially eliminated trout from East Mill Creek, located in southeast Idaho.
Addressing the proposed plan in an Op-Ed piece in the Idaho State Journal, Chuck Trost, a retired biology professor from Idaho State University writes, “The Blackfoot Reservoir is marginal habitat for cutthroat trout to begin with because of the tremendous load of nutrients in it, presumably from agricultural runoff. I have kayaked out to Gull Island on this reservoir almost every year for the last 25 years. For the last ten years the water has looked like pea soup with all the algal bloom during the summer months. I would be surprised if there weren't a winter-kill of trout from low oxygen levels when the algae die off. Most non-game fish can handle anoxic conditions, but not trout.”
Furthermore, other studies have shown that the pelican’s diet is 90% "trash," or nongame fish – chubs, suckers and carp – meaning rainbow and cutthroat trout are a small part of their diet.
The IDFG has already been taking measures to reduce white pelicans breeding in the state. They’ve been hazing birds (making loud noises to disturb the birds) and obtained a United States Fish and Wildlife Service license to kill 50 birds per year. (Although pelicans are technically protected under the Migratory Bird Treaty Act of 1918, the USFWS has the right to waive this protection.)