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Airport Wildlife Management Bulletin No. 35


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AIRPORT WILDLIFE MANAGEMENT

Airport Wildlife Management and Planning Update Double-crested Cormorants

BULLETIN no 35 - Summer 2005

Airport Wildlife Management Bulletin Logo

A new aviation threat
Issues and concerns
Quick Facts
Did you know…?
Controlling Cormorants
Dispersal
Exclusion
Removal
Significant incidents and data trends from FAA/USDA database
Update — Airport Wildlife Planning and Management Regulation
Smithsonian species-identification service

The Double-crested Cormorant

The Double-crested Cormorant is a large, greenish-black water bird with a slender hooked bill, orange facial skin and webbed feet. The bird is named for the two small tufts of feathers that appear on either side of adults’ heads in spring plumage.

There are 30 Cormorant species worldwide; six are found in North America. The Double-crested Cormorant is most widespread, and can be found throughout the continent—even around large inland bodies of fresh water.

A new aviation threat

Cormorants are not a new species in Canada; however, they are a relatively new threat to aircraft due to increasing populations, specifically in the Great Lakes region of Ontario. The Double-crested Cormorant began colonizing the Great Lakes area in the early 1900s. Population numbers peaked in the 1940s, and then declined to low levels in the late 60s. Since then, Cormorant populations have rebounded and today are the highest on record.

The recovery of this species is attributed primarily to:

  • bans in the late 1960s on DDT and other environmental contaminants, which caused egg-shell thinning and reproductive failure; and
  • an increase in available food sources—particularly small nonnative baitfish such as smelt and alewives, which are the birds’ primary food source in the Great Lakes basin.

Information provided by the Ontario Ministry of Natural Resources indicates that by 1999 the number of Cormorant nesting pairs had increased nearly 400-fold since the DDTinduced lows of the late 60s. In the decades since, Cormorants have expanded their North American range considerably.

 

Issues and concerns

The growing population of Double-crested Cormorants has been linked to multiple negative impacts on fisheries, aquaculture, natural habitats, colonial nesting birds and aircraft. In response, resource managers have undertaken extensive monitoring and increased management of the species.

Although Cormorants do not commonly nest on or feed at airports, the body size and density of these birds—coupled with their flocking behaviour—mean they pose particular hazards when flying through established aircraft approach and departure paths. In fact, according to Dr. Richard Dolbeer of the United States Department of Agriculture (USDA), the dense body of a five-pound Cormorant has the potential to do as much damage to an aircraft engine as a 15-pound Canada goose.

Quick Facts

Common name: Double-crested Cormorant
Scientific name: Phalocrocorax Auritus
Average weight: 1.9 kg
Potential lifespan: 23 years
Average clutch size: 3 – 4 birds
Number of broods per year: 1
Nesting: on ground or tree branches near water
Protective legislation: provincial
Hunting: not permitted

 

Did you know…?

  • The average Cormorant weighs approximately 1.9 kg (4.2 lbs) and will eat about 25% of its weight (approximately 0.48 kg; 1.0 lb) in fish each day.
  • Most adult Cormorants reside on the Great Lakes from mid-April to late August or early September (approximately 135 days).

Controlling Cormorants

Successful Cormorant management practices at or near airports result only from thorough studies that monitor area bird activities and populations. With a clear understanding of Cormorant movements, numbers and behaviour, wildlife personnel can draw on a range of management techniques that have proven successful throughout North America. As with any wildlife management program, it is important to integrate a variety of techniques to ensure long-term success.

Dispersal

Dispersal of Cormorant roosts should be undertaken only by qualified wildlife biologists to improve success rates and ensure, for example, that birds are not moved to areas where they could pose greater threats to aircraft operations. Once a roost has been dispersed, ongoing monitoring will help ensure that birds do not return.

Since Cormorants are highly susceptible to disturbance, harassment techniques can be quite effective. In some cases, continual human presence can discourage Cormorant nesting and roosting. Pyrotechnics, including various noise-making shells fired from shotguns, starter and flare pistols, have proven effective for startling and dispersing this species. Experts in the United States have had success using red lasers to disperse Cormorants from night roosts.

 

Exclusion

Remove access to all on-airport sources of food, water and shelter. As Cormorants’ diets primarily include small bait-sized fish and various aquatic insects, these birds can be deterred from using bodies of water over which netting and over-wiring can be deployed.

Removal

If Cormorant sightings or incidents are common on or near an airport, the first step is to monitor bird activities in relation to flight paths. This baseline information is crucial to the creation of an effective, integrated management plan that can reduce the risk to aircraft operations.

Since Cormorant hunting is illegal, specific permits and provincial/ territorial-authority approval are required before implementing any lethal control or population management. Lethal control of Cormorants can be applied to reinforce dispersal methods as part of an integrated program. The occasional killing of a bird in an airport environment may also be necessary to prevent habituation.

While not an effective solution for the immediate future, many jurisdictions are implementing egg-oiling programs to prevent further Cormorant population growth. In other areas culls have been necessary to halt damage inflicted on habitat and fish stocks.

Significant incidents and data trends from FAA/USDA database

The FAA/USDA database shows an increasing trend in the number of Cormorant strikes. A number of significant incidents are described below.

July 5, 1998

Piper Commanche, en route. The pilot reports not having seen an approaching Double-crested Cormorant, which penetrated the windshield. The pilot suffered facial lacerations from windshield fragments.

March 31, 2003

An Embraer ERJ 135 was on climb-out from JFK International when a Double-crested Cormorant struck the wing, making a large dent in the leading edge. The aircraft made a precautionary landing; repair costs are unknown.

October 19, 2003

A B-767 on climb-out at 200 ft. AGL struck a flock of more than 20 Double-crested Cormorants, ingesting at least one. There were immediate indications of right-side engine surge, including compressor stall and smoke. The engine was shut down and an overweight landing was made without incident. The nose cowl was dented and punctured, and there was significant fan blade damage. Hydraulic lines were leaking, and several bolts were sheared from the inside of the engine. The aircraft was towed to the ramp. The aircraft was out of service for three days; cost of repairs was USD$1.7 million.

August 31, 2004

On climb-out at 4800 ft. AGL, approximately five miles from the airport, a B-737 ingested a Double-crested Cormorant. Engine vibrations prompted the crew to make a precautionary landing. The aircraft was out of service for approximately six hours. Six fan blades were replaced at an estimated cost of USD$61,000. Other costs totaled USD$7,000.

September 16, 2004

On climb-out at 3000 ft. AGL from Chicago O’Hare, an MD-80 struck a flock of Cormorants. Several birds were ingested causing an engine failure and fire. Engine debris was reported to have fallen on a neighbourhood in suburban Chicago. The aircraft was able to return to the airport and make an emergency landing. Estimated cost of damage: USD$179,000; other costs, USD$6,885.

 

Update — Airport Wildlife Planning and Management Regulation

The new wildlife planning and management regulation was presented to the Canadian Aviation Regulation Advisory Council (CARAC) in 2001 and published in Canada Gazette I on May 14, 2005. Interested parties were invited to provide comments within 30 days. All comments are being addressed by Transport Canada, which expects implementation of the regulation by January 1, 2006.

Full text of both the regulation and regulatory impact statement can be found online at:
http://www.canadagazette.gc.ca/archives/p1/2005/2005-05-14/html/reg7-eng.html

In order to assist airport operators with the implementation of the Airport Wildlife Planning and Management Regulation we have developed a step -by- step guide that outlines the airport wildlife risk assessment and management planning process. There is no requirement for airports to use the format provided in the template, however it does meet the requirements of the standard and allows airport operators to fill in the required information about their site.

This document can be found online at: http://www.tc.gc.ca/eng/civilaviation/standards/aerodromeairnav-standards-wildlifecontrol-menu-931.htm

Smithsonian species-identification service

Transport Canada has formalized an agreement with the Smithsonian Institution, Division of Birds, to have feathers from Canadian bird strike incidents/accidents identified free of charge. To help ensure ongoing reporting accuracy in Canada, the department requests that feather remains be sealed in a plastic bag and sent with the TC bird strike reporting form to:

Wildlife Control Specialist
Aerodromes & Air Navigation, Transport Canada
Place de Ville, Tower C
Ottawa, ON K1A 0N8

Responses with species identification will be sent by email.

Alternatively, the same package can be sent directly to the Smithsonian Institution:

Smithsonian Institution, Division of Birds
MRC 116, PO Box 37012
Washington, DC 20013-7012
USA

For more information on content in this bulletin, please contact:

Bruce MacKinnon
Wildlife Control Specialist
Aerodromes & Air Navigation, Transport Canada
Place de Ville, Tower C
Ottawa, ON K1A 0N8

Tel: (613) 990-0515
Email: mackinb@tc.gc.ca

Date modified:
2011-04-08