PENNSYLVANIA GAME COMMISSION BUREAU OF WILDLIFE MANAGEMENT RESEARCH DIVISION PROJECT ANNUAL JOB REPORT PROJECT CODE NO.: 06750 TITLE: Nongame Wildlife Research/Management JOB CODE NO.: 70004 TITLE: Colonial Nesting Bird Study PERIOD COVERED: 1 July 2001 to 30 June 2002 COOPERATING AGENCIES: Pennsylvania Science Office of The Nature Conservancy and the Pennsylvania Society for Ornithology; USDA Wildlife Services WORK LOCATION(S): Statewide PREPARED BY: Daniel W. Brauning DATE: 4 February 2002 Abstract: The objective of this project is to inventory and monitor colonial waterbird populations in Pennsylvania. Active nests were counted during calendar year 2001 at all known great egret and black-crowned night-heron colonies, and at a sample of great blue heron colonies. Surveys of most colonies followed techniques recommended by the Patuxent Wildlife Research Center and the October 2000 draft of the North American Colonial Waterbird Conservation Plan: direct counts in spring prior to leaf-out. A count of active nests was reported for 10 great blue heron colonies during 2001. Larger colonies selected for surveys experienced normal fluctuations, with one increasing and most decreasing slightly. A volunteer counted 418 nests at the Barrows colony in November 2001, compared with 426 nests the previous winter and 441 nests in 1999. Over the past 3 years, this colony has shown a steady gradual decline from a high of 441 nests; a decline of 5%. While great egret numbers continue to increase at the Wade Island colony, numbers of black-crowned night-herons there declined to 93 active nests, the lowest level since the colony has been surveyed. The colony at Creek Road, Lancaster County, remained stable at about 88 nests. Twenty-three active nests and 35 young birds were counted at the Kiwanis Lake black-crowned nightheron colony in York City. The local landowner in West Lawn reported 9 blackcrowned night-heron nests in 2001, a decline from recent years at this colony. However, 20 young fledged and only 3 large young were known to have been lost at this site. Approximately 3 yellow-crowned night-heron nests were located along the Conodoguinet Creek in Cumberland County, although no systematic survey of this species was conducted. At Wade Island, the highest count ever of great egret nests, 166 active nests, was made on 1 May 2001. USDA Wildlife Services unit in Pennsylvania was awarded a permit again in 2001 to remove ring-billed and herring gull nests from the General Electric plant in Erie. On 8 site visits, totals of 2,880 ring-billed gull nests with 7,082 eggs and 8,203 renests with 16,234 eggs were collected from the treatment area. Totals of 7 herring gull nests with 15 eggs and 33 renests with 34 eggs were also collected. A management plan for Wade Island, produced under contract by Terry Master, is summarized.
2 OBJECTIVES 1. The primary objective of this project is to inventory and monitor colonial bird populations and their breeding sites. Annual objectives are to survey a sample of great blue heron colonies and to survey all known great egret, black-crowned night-heron, and yellow-crowned night-heron colonies. PROCEDURES Active nests were counted during calendar year 2001 at all known great egret and black-crowned night-heron colonies and at a sample of large great blue heron colonies. Surveys of most colonies follow techniques recommended by the Patuxent Wildlife Research Center and the October 2000 draft of the North American Colonial Waterbird Conservation Plan: direct counts in spring prior to leaf-out. The survey technique used at the Barrows site by a volunteer, a groundbased count of remaining nest structures after leaf-fall, is also an acceptable technique for single-species colonies. Biologist Chuck Thoma and Technician Alan Keister each surveyed a sample of Pennsylvania s largest great blue heron colonies during April 2000. In addition, Game Commission personnel and volunteers reported counts from colonies around the Commonwealth. Biologist Cal Butchkoski conducted a thorough count of active nests at the multi-species colony at Wade Island, Dauphin County, on 1 May. In addition, he searched for yellowcrowned night-heron nests along the Conodoguinet Creek. FINDINGS Great Blue Heron Colonies A count of active nests was reported for 10 great blue heron colonies during 2001 (Table 1). The state s largest known colonies, selected for surveys, experienced normal fluctuations, with one increasing and most decreasing slightly. New colonies were documented as the result of environmental reviews and waterfowl surveys. Birding records documented a colony of 5 nests in Lancaster County, the first documented nesting in that county (Miller 2001). The nests, near Mount Joy, produced 12 young. This continues the pattern of population expansion, both in range (to the south) and number of colonies in the state. A volunteer counted 418 nests at the Barrows colony in November 2001 (Table 1), compared with 426 nests the previous winter and 441 nests in 1999. This colony is comprised of 3 major sub-colonies. Sub-colony A held 92 nests, subcolony B held 212 nests, and sub-colony C held 114 for a total of 418 nests. These numbers compare to 86, 211, and 129 nests for the respective sub-colonies in 2000. Two trees within sub-colony B support over 50 separate nests! Over the past 3 years, this colony has shown a steady gradual decline from a high of 441 nests, a decline of 5%. Attention should be given to the colony to assure that its numbers remain stable. Special Concern Species Black-crowned night-heron The black-crowned night-heron (BCNH) population in Pennsylvania remains at a perilous level (Table 2). While great egret numbers continue to increase at the Wade Island colony, numbers of black-crowned night-herons declined to the lowest count since the colony has been surveyed, 93 active nests. Other known colonies fared a little better. The colony at Creek Road, Lancaster County, remained stable at about 88 nests. Peter Robinson counted 23 active nests on 16 May with 35 young birds on 27 June at the Kiwanis Lake colony in York City. The local landowner in West Lawn, June Brown, reported that there were 9
3 nests in 2001, a decline from recent years. However, 20 young fledged and only 3 large young were known to have been lost at this site. This is the eleventh year that the BCNH have nested in 70-foot tall spruce trees in this residential area. This area represents the potential for black-crowned night-herons, both in terms of habitat plasticity and of conflicts with humans. Yellow-crowned night-heron Approximately 3 yellow-crowned night-heron nests were located along the Conodoguinet Creek in Cumberland County, although no systematic survey of this species was conducted. No nests were found along the Conestoga Creek in the Brownstown, Lancaster County area; efforts were made only after leaf-out and were considered incomplete. On 12 May and 29 May, Al Spiese saw 1 yellow-crowned night-heron fly into a tree at the Kiwanis Lake black-crown colony, but could not see a nest, because the foliage was too thick. The status of this rare heron remains unclear. Great egret The highest count ever of egret nests at Wade Island was made on 1 May of 2001. One hundred sixty-six active nests were counted during the annual survey. A pair of egrets was observed at a nest at the Kiwanis Lake night-heron colony for much of the spring and summer (Al Spiese, personal communication). On 24 June, the nest was noted to have been destroyed. Other Colonial Birds USDA Wildlife Services unit in Pennsylvania was awarded a permit again in 2001 to remove ring-billed and herring gull nests from the General Electric plant in Erie (McWilliams 2001). The treatment area was extended from the 2000 season to cover the entire colony this year. There were approximately 8,000-8,500 nesting pairs of ring-billed gulls and approximately 25 nesting pairs of herring gulls. On 8 site visits 2,880 ring-billed gull nests with 7,082 eggs and 8,203 renests with 16,234 eggs were collected from the treatment area. Seven herring gull nests with 15 eggs and 33 renests with 34 eggs were also collected (C. Croson, personal communication). In addition to nest treatment, a methylanthranilate fogger was used as a non-lethal method to assist in dispersing the gull colony. This year's nest treatment activities proved to be highly effective in dispersing the gulls as the colony size reportedly decreased to only a few hundred birds by the end of June. Conservation and Management The nesting colony at Wade Island was evaluated by Dr. Terry Master, professor of biology at East Stoudsburg University. A plan was produced (Master 2001) and is summarized in Appendix 1. RECOMMENDATIONS 1. Closely monitor the Wade Island rookery and improve protection with additional restricted area signs. Attempt to reduce the annual survey effort to 2 hours. 2. Survey all black-crowned night-heron, yellow-crowned night-heron, and great egret colonies in 2002. 3. Educate private landowners hosting colonial waterbird colonies of the values of the birds and provide them with guidelines for colony protection. 4. With Pennsylvania Audubon, work with the York City parks department to provide protection for nesting black-crowned night-herons at Kiwanis Lake and obtain additional counts of the colony to determine the actual size.
4 5. Use several techniques to survey the Barrows colonies, possibly including aerial and post-breeding nest counts. 6. Evaluate risks and management issues at Wade Island, including island erosion and growth of nesting cormorant numbers, as potential factors in viability of site for night-herons and egrets. 2002. 7. Prepare for a statewide survey of all heron colonies in spring, 8. Assign a future new staff member of the Wildlife Diversity Section to serve as the Pennsylvania representative of the Colonial Waterbird Conservation Plan steering and advisory committee. LITERATURE CITED Master, T. 2001. Threat Assessment and Management Recommendations for Wade Island: A management plan. Pennsylvania Game Commission, Harrisburg, Pennsylvania, USA. McWilliams, G. M. 2001. The first successful ring-billed gull (Larus delawarensis) nesting in Pennsylvania. Pennsylvania Birds 13(1):62. Miller, R. 2001. Rare species report to Pennsylvania Ornithological Records Committee. Pennsylvania Birds. Table 1. Results of great blue heron colony surveys in Pennsylvania for 2001. 2001 nest count Previous nest count Year a Source County Colony Selected for survey Bradford Foster Branch * 0 39 1997 A. Keister Crawford Conneautee * 78 48 1997 C. Thoma Erie Juva * 120 124 2000 C. Thoma New Ireland * 46 51 2000 C. Thoma Lancaster Mount Joy 5 N PA Birds Lawrence Pulaski (Shenango) 24 N C. Thoma Mercer Barrows * 418 426 2000 T. Ross Northampton East Bangor 12 N I. Gregg Susquehanna Dr Lutz Woods * 75 80 2000 A. Keister Lenox * 30 33 2000 A. Keister Tioga Rt 49 15 N K. Mixon a N reflects a new colony with no previous survey.
5 Table 2. Number of active nests in all known colonies of black-crowned nightherons (BCNH), great egrets (GREG), and double-crested cormorants (DCCO) in Pennsylvania, 1995 to 2001. County Colony Name Species 1995 1996 1997 1998 1999 2000 2001 Berks West Lawn BCNH 15 12 16 9 Dauphin Wade Island BCNH 230 200 99 181 120 134 93 DCCO 1 1 2 4 9 11 GREG 136 155 131 144 159 148 166 Lancaster Creek Road BCNH 100 80 109 92 92 88 Philadelphia J. Heinz Refuge BCNH 24 12 York Kiwanis Lake BCNH 21 10 10 20 19 23 Lake William BCNH 4
Appendix A. Summary of Threat Assessment and Management Recommendations for Wade Island: A Management Plan submitted by Dr. Terry Master. 70004 6 Wade Island represents a unique avian spectacle in Pennsylvania. It is the state s largest herony overall and it is the largest concentration of both black-crowned night-heron and state-endangered great egret, and the state s only confirmed nesting location for double-crested cormorant. The major potential source of human disturbance to Wade Island involves boat/canoe traffic including casual recreation fishing, fishing tournaments, and the Susquehanna River Trail traffic. The amount and frequency of general boating activity may be enhanced by construction of the Dock Street Dam. This project, depending on the final height chosen, would also further increase the chance of people landing on the island and contribute to erosion currently in evidence on the east side of the island. Any rise in the height of the dam would impact the Wade Island colony to varying degrees, although no currently proposed scenario would flood the island. The current level of cormorant nesting activity probably does not warrant a control effort, although the potential for dramatic population increases in this species mandates close observation and does dictate that action be taken if nesting activity continues to increase at the current rate during the next two years. The following measures are proposed to protect the Wade Island colony: 1. Establish a buffer zone, marked with floating signs designating the island and its buffer zone as off limits to all boating activity and as a no wake zone, at least 100 meters from the perimeter of the island and preferably to a distance of 200 meters. 2. Begin erosion control along the east side of the island. 3. More clearly designate Wade Island as off limits to River Trail enthusiasts and include proposed buffer zone limits on all literature pertaining to the trail. 4. Oppose any attempt to raise the current height of the Dock Street Dam, or at least advocate the lowest alternative height. 5. Monitor both the nesting double-crested cormorant population and total population precisely and begin control measures if the cormorant nesting population continues to increase for the next two years (through 2003). Current monitoring efforts are excellent with regards to numbers of nesting pairs of herons, egrets, and cormorants. Data on nesting productivity would also be extremely valuable.