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Introduction To The Symposium On Double-Crested Cormorants: Population Status And Management Issues In The Midwest, Stephen J. Lewis, D.V. (Chip) Weseloh

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Populations of double-crested cormorants (Phalacrocorax auritus) have increased dramatically in the last 2 decades, particularly in the Great Lakes and the Southeastern United States. Their food habits and propensity for killing the trees in which they nest and roost have made cormorants the subject of much controversy. Cormorants affect—or are perceived to affect—sport fishing, aquaculture operations, vegetation, and other colonial waterbirds. Anglers, aquaculturists, resort operators, lakehome owners, politicians, and others are calling for a solution to these problems. This symposium was convened to provide information that will help conservation agencies and others make sound resource management decisions about …

The Problems Of Being Successful: Managing Interactions Between Humans And Double-Crested Cormorants, Douglas Siegel-Causey

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

The natural history, behavior, and ecology of double-crested cormorants (Phalacrocorax auritus) predispose this species for conflict with human sport and commercial fisheries. Cormorants breed early in life, have large broods, are efficient predators even in marginal conditions, seem to be able to adjust colony sizes quickly in response to local conditions, and have limited requirements for feeding and nesting habitats. A survey of the past history of successes and failures in managing cormorants reveals that economic impact is greatest with aquaculture and least in sport fisheries. Research during the past 5 years suggests that some control methods like …

Impact Of Double-Crested Cormorant Predation On The Yellow Perch Population In The Les Cheneaux Islands Of Michigan, Glenn Y. Belyea, Susan L. Maruca, James S. Diana, Philip J. Schneeberger, Steve J. Scott, Richard D. Clark Jr., James P. Ludwig, Cheryl L. Summer

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

The Michigan Department of Natural Resources, in conjunction with the University of Michigan and the U.S. Fish and Wildlife Service, initiated a research study to determine the impact of double-crested cormorants (Phalacrocorax auritus) on the yellow perch (Perca flavescens) population in the Les Cheneaux Islands area of northern Lake Huron. Aerial and nesting colony counts were conducted to monitor cormorant abundance. Creel census counts and tagging of 8,400 perch were used to study perch abundance. We collected 373 cormorants to study food habits via stomach-content analysis. We found that (1) cormorants fed heavily on yellow perch …

Double-Crested Cormorant Culling In The St. Lawrence River Estuary: Results Of A 5-Year Program, J. Bedard, A. Nadeau, M. Lepage

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Modeling indicated that lowering the doublecrested cormorant population from 17,361 to 10,000 pairs could be attained only by a combination of techniques: culling breeding birds in arboreal colonies to lower breeding stock and egg spraying in accessible ground nests to lower recruitment. The 5-year program was launched in 1989; culling was halted 4 years later because the population had fallen below the threshold of 10,000 breeding pairs. A greater vulnerability of males to shooting (203:100) probably accounted for the faster-than-predicted drop in numbers. Egg spraying spanned the entire 5-year period, during which 25,095 nests were treated with inert mineral oil. …

Front Matter And Contents

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Nesting Populations Of Double-Crested Cormorants In The United States And Canada, Laura A. Tyson, Jerrold L. Belant, Francesca J. Cuthbert, D.V. (Chip) Weseloh

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Double-crested cormorants (Phalacrocorax auritus) are receiving increasing attention in North America because of depredations at aquaculture facilities and alleged impacts on sport and commercial fisheries. We obtained recent (most since 1994) estimates for the number of nesting double-crested cormorants in the United States and Canada from published references and by conducting telephone interviews with State and Provincial biologists. Using published data, we also determined annual rates of change in the number of cormorants since about 1990. The estimated minimum number of nesting pairs (colonies) of double-crested cormorants was 372,000 (852). Most cormorants nested in the Interior region (68 …

Changes In The Status, Distribution, And Management Of Double-Crested Cormorants In Wisconsin, Summer W. Matteson, Paul W. Rasmussen, Kenneth L. Stromborg, Thomas I. Meier, Julie Van Stappen, Eric C. Nelson

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

We reviewed and summarized historical data and conducted population surveys from 1973 through 1997 to determine the breeding status and distribution of doublecrested cormorants (Phalacrocorax auritus) in Wisconsin. Breeding cormorants historically occupied large, isolated lakes and wetlands in northern Wisconsin, but there were no known nesting sites until 1919, when cormorants were reported nesting on Lake Wisconsin in south-central Wisconsin. From the 1920’s to the 1950’s, cormorants occupied 17 colony sites in 16 counties, though no more than 7 sites were occupied during any particular year. From the 1950’s to the early 1970’s, the number of cormorant nests …

Diet Of The Double-Crested Cormorant In Western Lake Erie, Michael T. Bur, Sandra L. Tinnirello, Charles D. Lovell, Jeff T. Tyson

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Sport and commercial fishing interest groups are concerned about potential impacts double-crested cormorants (Phalacrocorax auritus) may have on fish species. Our objectives for this study were to determine the diet of the cormorant in western Lake Erie and the diet overlap and competition for resources with piscivorous fish, such as walleye (Stizostedion vitreum.) The stomach contents of 302 double-crested cormorants collected in western Lake Erie consisted primarily of young-of-the-year gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides,) and freshwater drum (Aplodinotus grunniens). In the spring, freshwater drum were the most …

Double-Crested Cormorant Impacts On Sport Fish: Literature Review, Agency Survey, And Strategies, John L. Trapp, Stephen J. Lewis, Diane M. Pence

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

In response to concerns expressed by anglers, the U.S. Fish and Wildlife Service conducted an extensive review of published studies done throughout the United States and Canada on the impacts of double-crested cormorants (Phalacrocorax auritus) on sport-fish populations in open waters. The literature review indicated that fish species valued by sport and commercial anglers make up a very small proportion of the cormorants’ diet and that these birds have a minor effect on fish populations compared to the effects of sport and commercial fishing, natural predation, and other mortality factors. The Service sent a questionnaire to State agencies, …

Strategies To Reduce Double-Crested Cormorant Depredation At Aquaculture Facilities In Mississippi, David S. Reinhold, Charles A. (Bo) Sloan

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Double-crested cormorant (Phalacrocorax auritus) depredation throughout the Southeastern United States has been on the increase over the past 20 years. The increase in depredation coincides with the growth of the aquaculture industry and an expansion of double-crested cormorant wintering populations throughout the Southeast. The U.S. Department of Agriculture–Animal and Plant Health Inspection Service–Wildlife Services plays a major role in reducing double-crested cormorant damage. Nonlethal harassment on farms, dispersal from night roosts, and lethal control have reduced double-crested cormorant depredation at aquaculture farms in Mississippi. However, the efficiency and compatibility of current methods of reducing double-crested cormorant depredation must …

Possible Effects Of Catfish Exploitation On Overwinter Body Condition Of Double-Crested Cormorants, James F. Glahn, Mark E. Tobin, J. Brent Harrel

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Concurrent with the rapid growth of the Mississippi catfish industry during the 1980’s, there was evidence of similar growth of double-crested cormorant (Phalacrocorax auritus) populations wintering in the delta region of Mississippi. Observational and food habits studies indicate that this expansive industry, incorporating more than 100,000 acres of ponds, provides an enormous food base for overwintering populations estimated in recent years to exceed 50,000 birds. As much as 75 percent of the diet in certain roosting areas of the Mississippi delta consisted of catfish, and according to bioenergetic models cormorants can exploit as much as 940 metric tons …

A Geographic Information System To Monitor Nest Distributions Of Double-Crested Cormorants And Black-Crowned Night-Herons At Shared Colony Sites Near Toronto, Canada, S. Jarvie, H. Blokpoel, T. Chipperfield

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

In the early 1990’s, it became apparent that the rapid colonization of Tommy Thompson Park on Lake Ontario near Toronto by double-crested cormorants (Phalacrocorax auritus) would eventually affect the existing colonies of blackcrowned night-herons (Nycticorax nycticorax) owing to competition for nest sites and destruction of nest trees. As a result, monitoring of these two species was expanded in 1992 by individually marking all nest trees (using permanent metal tree tags) and by recording the numbers of heron and cormorant nests for all nest trees. In 1996, professional surveyors determined the exact locations of nest trees. We have developed …

Colonial Waterbird Nesting On West Sister Island National Wildlife Refuge And The Arrival Of Double-Crested Cormorants, Mark C. Shieldcastle, Larry Martin

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Recent survey data have shown the importance of West Sister Island National Wildlife Refuge, Lake Erie, to nesting waders. About 40 percent of all herons and egrets nesting in the U.S. Great Lakes are found there, including the Great Lakes’ largest colonies of great blue heron (Ardea herodias), great egret (Ardea alba), and black-crowned nightheron (Nycticorax nycticorax), and the largest of two snowy egret (Egretta thula). West Sister Island’s importance to Ohio has grown in recent decades with the loss of smaller mainland colonies of waders, especially the black-crowned night-heron. The double-crested …

Appendix 1: Authors' Affiliations

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Authors' affiliations

Double-Crested Cormorants In The Midwest: Symposium Summary, Francesca J. Cuthbert

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Populations of double-crested cormorants (DCCO’s, Phalacrocorax auritus) have increased dramatically in North America during the past 2 decades (1978–98), especially in the Great Lakes region and Southeastern United States. Concern about the impact, real or imagined, of DCCO’s on economics and ecosystem health has risen in parallel to the increase in cormorant numbers.

A daylong symposium on this subject was opened by Stephen Lewis and D. V. (Chip) Weseloh, who introduced the audience to the general problems associated with cormorants in the Midwest. The moderators identified the following symposium objectives: (1) to provide current information on the status and …

Fish Losses To Double-Crested Cormorant Predation In Eastern Lake Ontario, 1992–97, Robert M. Ross, James H. Johnson

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

We examined 4,848 regurgitated digestive pellets of double-crested cormorants (Phalacrocorax auritus) over a 6-year period (1992–97) to estimate annual predation on sport and other fishes in the eastern basin of Lake Ontario. We found more than 51,000 fish of 28 species. Using a model that incorporates annual colony nest counts; fledgling production rates; adult, immature, and young-of-year residence times (seasonal); estimates of mean number of fish per pellet and mean fish size; and a fecal pathway correction factor (4.0 percent), we estimate total annual number of fish consumed by cormorants in the eastern basin of Lake Ontario to …

Review Of The Population Status And Management Of Double-Crested Cormorants In Ontario, C. Korfanty, W.G. Miyasaki, J.L. Harcus

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

We prepared this review of the status and management of double-crested cormorants (Phalacrocorax auritus) in Ontario, with management options, in response to concerns expressed about possible negative impacts of large numbers of the birds on fish stocks, and vulnerable, threatened and endangered species. Double-crested cormorants are native to Ontario and were first recorded breeding on Lake of the Woods in northwestern Ontario in the late 1700’s. The birds spread eastward to colonize all of the Great Lakes by the 1930’s. A decline in cormorant populations on the Great Lakes from the 1950’s to the 1970’s has been attributed …

Information Needs For The Double-Crested Cormorant In Midwestern North America, As Identified By An Audience Survey , D.V. (Chip) Weseloh, Stephen J. Lewis

Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest

Double-crested cormorant (DCCO) research needs and data gaps were identified in the early 1990’s by Erwin (1995) and Nisbet (1995). Erwin (1995) recommended four areas of research: (1) large-scale banding and marking to determine age- and sex specific survival and fecundity, (2) studies of movements during migration and winter, (3) assessment of limiting factors such as contaminants and disease, especially in light of recent Newcastle disease in cormorants, and (4) evaluation of economic impacts of cormorants on cultured fishes and ways to reduce predation by fish-eating birds.

Fall Field Report, August-November 1997, W. Ross Silcock, Joel G. Jorgensen

Nebraska Bird Review

Notable this Fall was very heavy coverage of the Panhandle during Sep-Oct, which yielded several outstanding records (all, of course, pending NOURC approval). Incredible were first Panhandle records of Golden-winged, Chestnut-sided, Bay-breasted, and Prothonotary Warblers, 3rd record of Northern Waterthrush, and 4th record of Blackburnian Warbler. Philadelphia Vireo was found in the Panhandle for the 3rd time. Important also were 3 records of Hammond's Flycatcher, the 3rd-6th for the state, and likely a regular migrant, and 5 of Cassin's vireo, previously known only by 2 specimens. Finally, from the Panhandle, 4 reports of Blue-Gray Gnatcatcher may be changing the status …

Notes On The Nesting Biology Of Pygmy Nuthatches In Nebraska, Wayne Mollhoff

Nebraska Bird Review

Introduction

Pygmy Nuthatches (Sitta pygmaea) were considered to be no more than casual or rare winter visitors to the northwest part of Nebraska by previous investigators (Bruner et al. 1904; Swenk 1918; Haecker et al. 1945; Rapp et al. 1958, 1971). I. S. Trostler's earlier comment that the species was "a rare resident, breeds in Omaha" (Bruner 1896) was later felt to be in error, as evidenced by Bruner's later comment that it was, "A fall and winter visitor . . . not breeding in the state" (Bruner et al. 1904).

The first evidence of breeding was the …

Nebraska Bird Review (December 1997) 65 (4), Whole Issue

Nebraska Bird Review

Whooping Crane Sightings, August 1997-January 1998 … 146

A Probable Nesting of Clark's Nutcracker (Nucifraga columbiana) in Nebraska … 147

Notes on the Nesting Biology of Pygmy Nuthatches in Nebraska … 150

Fall Field Report, August-November 1997 … 159

Observers for Fall Field Report … 178

Black-throated Sparrow Banded in Omaha, Nebraska … 179

Editor's Comments … 179

Index to Volume 65 (compiled by R. G. Cortelyou) … 180

The Brood-Rearing Habitat, Brood Home Range, And Fecundity Of The Snowy Plover (Charadrius Alexandrinus) In Coastal Southern Texas, Jeffery R. Rupert

Theses and Dissertations - UTB/UTPA

Habitat fragmentation has been shown to have negative effects on avian communities. I looked at the effects of corridor width and vegetation characteristics on nesting densities and breeding success of birds in the Lower Rio Grande Valley. There were definite trends in this study of increasing species richness and nesting densities with increasing corridor widths. Multiple regression revealed little correlation between tree density, diameter at breast height, tree height, canopy cover and ground cover with nesting density or nesting success. However, factors such as parasitism by the Bronzed Cowbird (Molothrus aeneus) and predation were much greater in narrower corridors. This …

Kentucky Warbler (Vol. 73, No. 4), Kentucky Library Research Collections

Kentucky Warbler

No abstract provided.

Nebraska Bird Review (September 1997) 65(3), Whole Issue

Nebraska Bird Review

Summer Field Report, June-July 1997 … 102

1996 (Eighth) Report of the NOU Records Committee … 115

Notes on Bird Sightings in Nebraska … 126

International Shorebird Survey Report for southeastern Nebraska - Spring 1997 … 127

Mountain Plover Nest in Kimball County … 131

Whooping Crane Sightings during March-May 1997 Migration … 132

Shorebird Migration in the Eastern Rainwater Basin - Spring 1997 … 133

Two Hybrid Diving Ducks at Cunningham Lake, Douglas County … 135

Spring 1997 Bird Counts during Tristate Meeting, and for North Platte - Lincoln County … 137

Remembering Doris Gates, a Great Teacher … …

1996 (Eighth) Report Of The Nou Records Committee, Mark A. Brogie

Nebraska Bird Review

The functions and methods of the NOU Records Committee are described in its bylaws (NOU Records Committee 1986). The committee's purpose is to provide a procedure for documenting unusual bird sightings and to establish a list of all documented birds for Nebraska. THE OFFICIAL LIST OF THE BIRDS OF NEBRASKA was first published in 1988 (NOU Records Committee 1988) and has been appended six times (Mollhoff 1989, Grenon 1990, 1991, Gubanyi l996a, 1996b, 1996c). An update of THE OFFICIAL LIST OF THE BIRDS OF NEBRASKA was last published in 1997 (NOU Records Committee 1997) and includes the additions and changes …

Notes On Bird Sightings In Nebraska, L. Iola Pennington

Nebraska Bird Review

1997 Report for Wauneta area, Chase County. I have seen 49 species, including 20 Turkey Vultures, many Wild Turkeys, a covey of Northern Bobwhite near my house, a Ruby-throated Hummingbird in my garden flowers such as Gilia, and a Black-headed Grosbeak—a first for my acreage. On 6 September, a male Northern Cardinal brought two young to one of the seven water pans I keep for birds and animals. Other species listed in the area: Great Blue Heron, Gadwall, American Kestrel, Ring-necked Pheasant, Killdeer, Rock Dove, Mourning Dove, Yellow-billed Cuckoo, Common Nighthawk, Chimney Swift, Belted Kingfisher, Red-headed Woodpecker, Hairy Woodpecker, …

Mountain Plover Nest In Kimball County, Stephen J. Dinsmore

Nebraska Bird Review

On 18 May 1995 I observed two adult Mountain Plovers 5 mi west and 1.25 mi north of Bushnell in southwest Kimball county. The birds were in an area of short-grass prairie interspersed with clumps of prickly pear and bare ground. I observed both birds almost continuously from 1-2 p.m. MDT. The first bird was along the road south of the fenceline, just after the road climbs on top of the plateau. The second bird was about 0.1 mi to the north on the west side of the road. Both birds were medium-sized, plain shorebirds, similar in shape and posture …

Whooping Crane Sightings During March-May 1997 Migration, Steven Anschutz

Nebraska Bird Review

During the 1996-97 winter, 158 (143 adult/subadult and 15 juvenile) Whooping Cranes stayed at the Aransas National Wildlife Refuge in Texas. Two early migrants in Nebraska were an adult-plumaged bird first observed on 9 March, and a juvenile confirmed on 19 March. Neither of these birds wintered at Aransas, so the total population was therefore 160 (144 adult/subadult and 16 juvenile). All 158 cranes wintering at Aransas were present 3 April, but by 10 April, about 103 cranes had begun to migrate, and by 24 April, only 13 cranes were still at Aransas. All cranes had migrated by 6 May.

Summer Field Report, June-July 1997, W. Ross Silcock, Joel G. Jorgensen

Nebraska Bird Review

A couple of preliminary notes: in the accounts below we have noted for several species "Reports were routine." This means that these species, mostly common in occurrence, were indeed present and reported, but the reports did not include unusual arrival or departure dates or high counts. For this Summer Report, observers are encouraged to report high counts on their BBS routes, as well as nesting data such as egg and fledging dates. Finally, this report includes a few observations from 1996.

In general, this was a rather routine summer period. The only real rarity was, however, a good one, a …

Shorebird Migration In The Eastern Rainwater Basin—Spring 1997, Joel G. Jorgensen

Nebraska Bird Review

The Rainwater Basin is arguably Nebraska's most productive area for observing migrant shorebirds, especially in spring. After several years of irregular shorebirding in the region, in 1997 I decided to perform regular shorebird censuses in the eastern portion of the RWB (eRWB).