The Everglades

Dr. Kushlan’s research and conservation studies in the Everglades principally revolved around addressing questions of how seasonal fluctuations in hydrology drive the system’s ecology, conservation of its wildlife, and its restoration.

Much of this research is organized around a repeated question: What are the relationships between seasonal variation in water levels and biological responses of wetland animals? The designs of studies addressing this question are characterized by use of natural and artificial experiments and development of predictive models.

Exploring the range of animal accommodation to environmental variability and insights into the hydrological management of seasonal wetlands remain fundamentally and practically pertinent and have been extrapolated to other wetland systems worldwide.

Studies also characterized the status of an array of species of concern in the greater Everglades ecosystem.

More details and relevant publications are presented below for the several lines of Everglades research . For information about waterbird research in the Everglades, please visit the Waterbirds Research page.

For access to the articles cited below, please go to the Articles page. For more information about cited books, please visit the Books page.

The Everglades: Aquatic Animals

This line of research broadly investigates how aquatic organisms accommodate to the seasonality of wetlands. These organisms  serve as the prey base for wildlife, including wading birds and crocodilians. Studies involved an array of species of fish, crustaceans and mollusks as hydrological conditions vary seasonally and annually. Because determining numbers of fish in wetlands long had been a serious constraint to their study, appropriate sampling devices and sampling protocols were designed, tested and modeled. Known widely as the Kushlan throw trap, the final methodology has been adopted by scientists and wetland managers in many parts of the world. Among the basic results of these studies were the first quantitative analysis of the seasonally changing aquatic fauna of role of the alligator pond within the southern Florida wetlands, the role of annual patterns of hydrology on aquatic animal populations, and the first full delineation of the fresh water fish fauna of the region.

Kushlan, J.A.  1973. Differential responses to drought in two species of Fundulus.  Copeia 1973:808-809.

Kushlan, J.A. and T.E. Lodge. 1974.  Ecological and distributional notes on the freshwater fish of southern Florida.  Florida Scientist 37:110-128.

Kushlan, J.A.  1974.  Quantitative sampling of fish populations in shallow, freshwater environments.  Transactions of the American Fisheries Society 103:348-352.        

Kushlan, J.A.  1974.  Effects of a natural fish kill on the water quality, plankton, and fish population of a pond in the Big Cypress Swamp, Florida.  Transactions of the American Fisheries Society 103:235-243.                        

Kushlan, J.A.  1975.  Population changes of the apple snail (Pomacea paludosa) in the southern Everglades.  Nautilus 89:21-23.

Kushlan, J.A.  1976.  Wading bird predation in a seasonally fluctuating pond.  Auk 93:464-476.

Kushlan, J.A.  1976.  Environmental stability and fish community diversity.  Ecology 57:821-825.

Loftus, W.F. and J.A. Kushlan. 1978.  Freshwater Fishes of Southern Florida. Florida State Museum, Gainesville FL, USA.

Kushlan, J.A. and M.S. Kushlan.  1979.  Observations on crayfish in the Everglades, Florida, USA. Crustaceana Suppl.  5:116-120.

Kushlan, J.A. and M.S. Kushlan.  1980.  Population fluctuations of the prawn, Palaemonetespaludosus, in the Everglades.  American Midland Naturalist 103:401-403.

Kushlan, J.A.  1980.  Population fluctuations of Everglades fishes.  Copeia 1980:870-874.

Kushlan, J.A.  1981. Sampling characteristics of enclosure fish traps. Transactions of the American Fisheries Society 110:557-562.

Loftus, W.F., J.A. Kushlan, and S.A. Voorhees.  1984.  Status of the mountain mullet southern Florida.  Florida Scientist 47:256-263.

Kushlan, J.A., S.A. Voorhees, W.F. Loftus, and P.C. Frohring.  1986.  Length, mass, and calorific relationships of Everglades animals.  Florida Scientist 49:65-79.

Jacobsen, T. and J.A. Kushlan.  1987.  Sources of sampling bias in enclosure fish trapping:  effects on estimates of density and diversity.  Fisheries Research 5:401-412.

Capone, T.A. and J.A. Kushlan.  1991.  Fish community structure in dry season stream pools.  Ecology 72:983-992.

The Everglades: Crocodilians

The American alligator is the animal most associated with the Everglades and this is the only environment in which alligators and American crocodiles occur together, yet prior to these studies, there were no substantive, quantitative investigations of either species in the Everglades Among the questions addressed were:

  • What is the role of the alligator’s characteristic pond habitat within the wetland landscape?
  • What are the alligator’s biological and behavioral responses to hydrological fluctuation?
  • What factors might be limiting the growth and distribution of crocodiles?
  • What conservation options are appropriate for alligators and crocodiles in southern Florida?

Several lines of research on the ecology of alligator ponds, also known as gator holes, resulted in  the first demonstration of the role such seasonal environments play in southern Florida’s wetlands as survival refugia for aquatic animals. This research  unraveled the complex interactions among alligators, foraging wading birds, fish populations, and water chemistry. The role of alligator ponds has since become part of the common interpretive knowledge base on the Everglades, widely taught to school children and interpreted to park visitors

Other crocodilian studies included the relationship of hydrology to such variables as alligator population size and trend, body condition and growth, nesting timing and success, behavior, land use and territoriality, food habits, and population genetics. Several new aspects of alligator biology were discovered through experimental studies.

Comprehensive studies of the potential limiting factors of the American crocodile population in southern Florida essentially found no limitations beyond artificial mortality and habitat protection. These studies provided the first base-line population estimate for the North American crocodile population.

Studies of both crocodilian species resulted in conservation recommendations, and for the crocodile, a conservation plan that was an important step in the population recovery that followed.

Kushlan, J.A.  1973.  Observations on maternal behavior in the American alligator, Alligator mississippiensis.  Herpetologica 29:256-267.

Kushlan, J.A.  1974.  Observations on the role of the American alligator (Alligator mississippiensis) in the southern Florida wetlands.  Copeia 1974:993-996.

Kushlan, J.A.  1974.  Effects of a natural fish kill on the water quality, plankton, and fish population of a pond in the Big Cypress Swamp, Florida.  Transactions of the American Fisheries Society 103:235-243.

Kushlan, J.A. and J.A. Browder.  1975.  Freshwater ecosystems, alligator hole.  Pp. 637-647 In: Carrying Capacity for Man Nature in South Florida.  (H.T. Odum and M.T. Brown, eds.)  Center for Wetlands, University of Florida, Gainesville, FL, USA.

Kushlan, J.A.  1976.  Wading bird predation in a seasonally fluctuating pond.  Auk 93:464-476.

Klukas, R., W.B. Robertson, Jr., J.C. Ogden, J.A. Kushlan, T. Hines, and H. W. Campbell.  1979.  American Crocodile Recovery Plan.  U.S. Fish and Wildlife Service, Atlanta, GA, USA. 

Kushlan, J.A.  1979.  Temperature and oxygen in an Everglades alligator pond.  Hydrobiologia  67:267-271.

Kushlan, J.A. and B.P. Hunt.  1979.  Limnology of an alligator pond in south Florida.  Florida Scientist 42:65-84.

Menzies, R.A., J.A. Kushlan, and H.C. Dessauer.  1979.  Low level of genetic variability in the American alligator (Alligator mississippiensis).  Isozyme Bulletin 12:61.

Kushlan, J.A. and M.S. Kushlan. 1980. Everglades alligator nests: nesting sites for marsh reptiles.  Copeia 1980:930-932.

Kushlan, J.A. and M.S. Kushlan.  1980.  The function of nest attendance in the American alligator.  Herpetologica 36:27-32.

Kushlan, J.A. and M.S. Kushlan. 1980. Water levels and alligator nesting in the Everglades. Second Conference on Scientific Research in National Parks, 1979. U.S. Department of Interior, Washington, DC, USA.

Kushlan, J.A. and J.C. Simon. 1981. Egg manipulation by the American alligator. Journal of Herpetology 15:451-454

Kushlan, J.A.  1982. The status of crocodilians in south Florida.  Pp. 99-107.  In: Crocodiles (D. Dietz and F.W. King, eds.) International Union for the Conservation of Nature and Natural Resources, Morges, Switzerland.

Kushlan, J.A. 1982. From the Everglades, one scientist’s view. Park Science 3(1):6-7.

Kushlan, J.A. and T. Jacobsen. 1984. Management of alligator nest flooding. National Park Service. South Florida Research Center 84/10.

Jacobsen, T. and J.A. Kushlan. 1984. Population status of the American alligator (Alligator mississippiensis) in Everglades National Park. South Florida Research Center, Everglades National Park.

Stoneburner, D.L. and J.A. Kushlan.  1984.  Heavy metals in southern Florida crocodile eggs.  Journal of Herpetology 18:192-193.

Hines, T., R. Klukas, J.A. Kushlan, P. Moler, J.C Ogden, and W.B. Robertson, Jr. 1984. American Crocodile Recovery Plan. US Fish and Wildlife Service, Atlanta GA, USA.

Jacobsen, T. and J.A. Kushlan. 1986.  Alligators in natural areas: choosing conservation policies consistent with local objectives.  Biological Conservation 36:181-196.  

Jacobsen, T. and J.A. Kushlan.  1986.  Alligator nest flooding in the southern Everglades.  Pp. 153-166, In: Crocodiles IUCN Publication New Series, Caracas, Venezuela.

Kushlan, J.A. and F.J. Mazzotti. 1986.  Population biology and status of the American crocodile in south Florida.  Pp. 188-194.  In: Crocodiles.  IUCN Publication New Series, Caracas, Venezuela.

Kushlan, J.A.  1986.  The Everglades: management of cumulative ecosystem degradation.  Pp. 61-82.  In: Managing Cumulative Effects in Florida Wetlands.  (E.D. Estevez, J. Miller, J. Morris, and R. Hamman, eds.).  New College Environmental Studies Program, Publication 37.  Omnipress, Madison, WI, USA.

Kushlan, J.A. 1988. Impact of water management on wildlife in the Florida Everglades. Pp. 231-243. In: Ecologia y Conservacion del Delta de los rios Usumacinta Y Grijalva (M. Chevez, ed). Instituto Nacional de Investigacion sobre Recursos Bioticos (INIREB) – Divison Regional Tabasco, Tabasco, Mexico.

Kushlan, J.A.  1988.  Conservation and management of the American crocodile.  Environmental Management 12:777-790.

Mazzotti, F., J.A. Kushlan, and A. Dunbar-Cooper.  1988.  Desiccation and cryptic nest flooding as causes of nest mortality in the American crocodile (Crocodylus acutus) in Everglades National Park, Florida. Florida Scientist 51:65-72.

Kushlan, J.A.  1989.  Wetlands and wildlife, the Everglades perspective.  Pp.773-796. In: Freshwater Wetlands and Wildlife (R.R. Sharitz and J.W. Gibbons, eds.)  Dept. of Energy Symposium Series No. 61. Oak Ridge, Tennessee, USA.

Jacobsen, T. and J.A. Kushlan  1989.  Growth dynamics in the American alligator. Journal of Zoology (London) 219:309-328.

Kushlan, J.A. and F. Mazzotti.  1989.  Population biology of the American crocodile. Journal of Herpetology 23:7-21.

Kushlan, J.A. and F. Mazzotti.  1989.  Historic and present distribution of the American crocodile in Florida.  Journal of Herpetology 23:1-7.

Kushlan, J.A. and T. Jacobsen.  1990.  Environmental variability and the reproductive success of Everglades alligators.  Journal of Herpetology 24:176-184.

Menzies, R.A. and J.A. Kushlan.  1991.  Genetic variation in populations of the American crocodile.  Journal of Herpetology 25:357-361.           

The Everglades: Population Status and Monitoring

In the 1970s, status and trends of many southern Florida species remained poorly understood. Their distributions were not documented and monitoring protocols did not exist for determining population sizes, assessing historic changes, or monitoring year-to-year fluctuations. available monitoring tolls were extremely limited. A series of studies determined the population status and monitoring options of some of these understudied species in southern Florida including aquatic invertebrates and fish, waterbirds, and listed species such as the Cape Sable Seaside Sparrow, Brown Pelican, Everglade Kite, Florida manatee, and Florida panther. The results provided a base-line understanding of status in and around the Everglades, crucial to future research and conservation efforts. Some of the results included:

  • Establishing protocols for monitoring freshwater fish and wading birds;
  • Pioneering surveys establishing the continued presence of the Florida panther in the Everglades and Big Cypress Swamp;
  • Determining population size, distribution and monitoring protocol for the endangered Cape Sable Seaside Sparrow;
  • Discovering population declines in fish-eating birds in Florida Bay attributable to reduced prey availability, anticipating later broader collapses of the bay’s ecosystem;
  • Status determinations of a number of more common species.

Several of the studies led directly to species recovery and other management plans, and together provided background for considerations of the potential roles of wildlife population information as indicators of ecosystem functioning and measures of resource management actions. 

Kushlan, J.A. and R.L. Paterson. 1972. Winter range of the Rusty Blackbird (Euphagus carolinus) in Florida. Florida Naturalist 45:129-130.

Kushlan, J.A. and E.J. Fisk. 1972. Range expansion of the Killdeer in Florida. Bird-banding 43:261-263.

Kushlan, J.A. 1973. White Ibis nesting in the Florida Everglades. Wilson Bulletin 85:230-231.

Kushlan, J.A. and T.E. Lodge. 1974. Ecological and distributional notes on the freshwater fish of southern Florida. Florida Scientist 37:110-128.

Kushlan, J.A. 1975. Population changes of the apple snail (Pomacea paludosa) in the southern Everglades. Nautilus 89:21-23.

Kushlan, J.A. and M.S. Kushlan. 1976. Winter bird census, Everglades marsh. American Birds 30:1066-1067.

Kushlan, J.A. and D.A. White. 1977. Nesting wading bird populations in southern Florida. Florida Scientist 40:65-72.

Kushlan, J.A. and D.A. White.  1977.  Laughing Gull colonies in extreme southern Florida.  Florida Field Naturalist 5:44-46.

Kushlan, J.A. and M.S. Kushlan. 1977. Breeding bird census, Everglades marsh. American Birds 31:83.

Kushlan, J.A. and W.B. Robertson, Jr. 1977. White Ibis nesting in the lower Florida Keys. Florida Field Naturalist 5:41-42.

Kushlan, J.A. and L.C. McEwan. 1978. Colonial birds in South Florida national parks, 1976-1977. Report T-545, US National Park Service, South Florida Research Center, Homestead, FL, USA.                                                                   

Kushlan, J.A. 1978. Wading bird use of the east Everglades. Florida Field Naturalist 6:46-47.

Kushlan, J.A.  1978.  White Pelican numbers in Everglades National Park.  Florida Field Naturalist 6:16.     

Reeves, K.A. and J A. Kushlan. 1978. Preliminary investigation of the Florida panther in Big Cypress Swamp. South Florida Research Center, Everglades National Park, Homestead, FL, USA.

Kushlan, J.A. 1978. The Florida panther in Everglades National Park. Everglades National Park, Homestead, FL, USA.

Klukas, R., W.B. Robertson, Jr., J.C. Ogden, J.A. Kushlan, T. Hines, and H.W. Campbell. 1979. American Crocodile Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, GA, USA. 

Kushlan, J.A.  1979.  Effects of helicopter censuses on wading bird colonies.  Journal of Wildlife Management 43:756-760.

Kushlan, J.A. and M.S. Kushlan. 1980. Population fluctuations of the prawn, Palaemonetespaludosus, in the Everglades. American Midland Naturalist 103:401-403.

Kushlan, J.A. 1980. Reintroduction of indigenous species to natural ecosystems. Environmental Management 4:93-94.

Alvarez, K.C., R.E. Baudy, R.C. Belden, B. Knoles, J.A. Kushlan, J.N. Layne, and P.C.H.  Pritchard.  1981. Florida Panther Recovery Plan.  U.S. Fish and Wildlife Service, Atlanta, GA, USA.

Kushlan, J.A. 1981. Sampling characteristics of enclosure fish traps. Transactions of the American Fisheries Society 110:557-562.

Kushlan, J.A. and F.J. Mazzotti. 1982. Status of the gopher tortoise in Everglades National Park. South Florida Research Center Report T-669. Homestead, FL, USA.

Kushlan, J.A.  1982. The Sandhill Crane in the Everglades.  Florida Field Naturalist 10:74-76

Kushlan, J.A. and L.C. McEwan. 1982.  Nesting phenology of the Double-crested Cormorant.  Wilson Bulletin 94:201-206.

Kushlan, J.A., O.L. Bass, Jr., and L.C. McEwan. 1982. Wintering waterfowl in the Everglades estuaries. American Birds 36:815-819.

Bass, O.L. and J.A. Kushlan. 1982. Status of the Osprey in Everglades National Park. South Florida Research Center Report M-679. National Park Service, Homestead, FL, USA.

Kushlan, J.A. and L.C. McEwan. 1982. Wintering waterfowl in Everglades National Park. South Florida Research Center Report T-679. National Park Service, Homestead, FL, USA.

Loftus, W.F. and J.A. Kushlan. 1982. The status of the Schaus swallowtail and the Bahama swallowtail butterflies in Biscayne National Park. South Florida Research Center Report M-649. National Park Service, Homestead, FL, USA.

Bass, O.L. and J.A. Kushlan. 1982. Status of the Cape Sable Sparrow. South Florida Research Center Report T-672. National Park Service, Homestead, FL, USA.

Kushlan, J.A. 1982. The status of crocodilians in south Florida. Pp. 99-107. In: Crocodiles (D. Dietz and F.W. King, eds.) IUCN, Morges, Switzerland.

Kushlan, J.A., O.L. Bass, Jr., L.L. Loope, W.B. Robertson, Jr., Peter C. Rosendahl, and D.L. Taylor. 1982. The Cape Sable Sparrow Management Plan. South Florida Research Center Report M-660. National Park Service, Homestead, FL, USA.

Steiner, T.M., O.L. Bass, and J.A. Kushlan. 1983. Status of the eastern indigo snake in southern Florida national parks and vicinity. South Florida Research Center Report 83.01. National Park Service, Homestead, FL, USA.

Kushlan, J.A. and O.L. Bass, Jr. 1983. Snail kite in the southern Everglades. Florida Field Naturalist 11:108-111.

Kushlan, J.A., O.L. Bass, Jr., L.L. Loope, W.B. Robertson, Jr., and D.L. Taylor. 1983. Cape Sable Sparrow Recovery Plan. US Fish and Wildlife Service. Atlanta, GA, USA.                                                             

Kushlan, J.A. and O.L. Bass, Jr.  1983.  Habitat use and the distribution of the Cape Sable Sparrow.  Pp. 139-146.  In: The Seaside Sparrow, its Biology and Management (T. Quay et al., eds.).  Occasional Papers North Carolina Biological Survey, 1983-5.

Kushlan, J.A. and O.L. Bass, Jr.  1983.  Decreases in the southern Florida Osprey population, a possible result of food stress.  Pp. 181-200.  In: Status and Management of Osprey and Eagles.  (D.M. Bird, ed.). Raptor Research Foundation, Montreal, Canada.

Kushlan, J.A. and O.L. Bass, Jr.  1983. Snail kite in the southern Everglades.  Florida Field Naturalist 11:108-111.

Kushlan, J.A.  1983.  Special species and ecosystem preserves: colonial waterbirds in U.S. national parks.  Environmental Management 7:201-207.

Kushlan, J.A.  1983.  Review: Everglade Kite Recovery Plan.  Florida Field Naturalist 11:117-119.

Kushlan, J.A. and F. Mazzotti.  1984.  Environmental effects on a coastal population of gopher tortoises.  Journal of Herpetology 18:231-239.

Loftus, W.F. and J.A. Kushlan.  1984.  Population fluctuations of the Schaus swallowtail (Lepidoptera; Papilionidae) on the islands of Biscayne Bay, Florida, with comments on the Bahama swallowtail.  Florida Entomologist 67:277-287.

Loftus, W.F., J.A. Kushlan, and S.A. Voorhees. 1984. Status of the mountain mullet in southern Florida.  Florida Scientist 47:256-263.

Stoneburner, D.L. and J.A. Kushlan. 1984. Heavy metals in southern Florida crocodile eggs. Journal of Herpetology 18:192-193.

Hines, T., R. Klukas, J.A. Kushlan, P. Moler, J.C Ogden, and W.B. Robertson, Jr. 1984. American crocodile recovery plan. US Fish and Wildlife Service, Atlanta, GA, USA.

Jacobsen, T. and J.A. Kushlan. 1984. Population status of the American alligator (Alligator mississippiensis) in Everglades National Park. South Florida Research Center, US National Park Service, Homestead,  FL, USA.

Kushlan, J.A. and P.C. Frohring.  1985.  Decreases in the Brown Pelican population in southern Florida.  Colonial Waterbirds 8:83-95.

Kushlan, J.A. 1985. Seasonal distribution of manatees in the Everglades estuary. Report #2, Water Resources Center, East Texas State University, Commerce, TX.

Kushlan, J.A. and D.A. White.  1985.  Least and Roseate Tern nesting sites in the Florida Keys.  Florida Field Naturalist 13:98-99.

Frohring, P.C. and J.A. Kushlan.  1986.  Nesting status and colony site variability of the Laughing Gull population in southern Florida.  Florida Field Naturalist 14:1-17.

Kushlan, J.A.  1986.  Atlantic loggerhead turtle nesting status in southwest Florida.  Herpetological Review 17:51-52.

Kushlan, J.A. 1986. Colonies, surveys, and sites: the terminology of colonial waterbird research. Colonial Waterbirds 9:119-120.

Kushlan, J.A. and F.J. Mazzotti. 1986. Population biology and status of the American crocodile in south Florida. Pp. 188-194. In: Crocodiles. IUCN Publication New Series. IUCN, Caracas, Venezuela.

Kushlan, J.A. and P.C. Frohring. 1986. History of the southern Florida Wood Stork population. Wilson Bulletin 92:368-386.

Jacobsen, T. and J.A. Kushlan. 1986.  Alligators in natural areas: choosing conservation policies consistent with local objectives.  Biological Conservation 36:181-196.

Kushlan, J.A. 1986  The Everglades: management of cumulative ecosystem degradation. Pp. 61-82. In: Managing Cumulative Effects in Florida Wetlands. (E.D. Estevez, J. Miller, J. Morris, and R. Hamman, eds.). New College Environmental Studies Program Publication 37. Omnipress, Madison, WI, USA

Kushlan, J.A.  1987.  Review: Recovery Plan for the U.S. Breeding Population of the Wood Stork. Colonial Waterbirds 10:259-262.

Jacobsen, T. and J.A. Kushlan. 1987. Sources of sampling bias in enclosure fish trapping: effects on estimates of density and diversity. Fisheries Research 5:401-412.

Kushlan, J.A.  1988.  Conservation and management of the American crocodile.  Environmental Management 12:777-790.

Frohring, P.C., D.P. Voorhees, and J.A. Kushlan.  1988.  History of wading bird populations in the Florida Everglades: a lesson in the use of historical information.  Colonial Waterbirds 11:328-335.

Kushlan, J.A. 1988. Impact of water management on wildlife in the Florida Everglades. Pp. 231-243. In: Ecologia y Conservacion del Delta de los rios Usumacinta Y Grijalva (Memorias) (M. Chevez, ed.).  Instituto Nacional de Investigacion sobre Recursos Bioticos (INIREB) – Divison Regional Tabasco, Tabasco, Mexico. 

Parnell, J.A., D.G. Ainley, H. Blokpoel, B. Cain, T.W. Custer, J.L. Dusi, S. Kress, J.A. Kushlan, W.E. Southern, L.E. Stenzel, and B.C. Thompson. 1988. Colonial waterbird management in North America. Colonial Waterbirds 11:129-169.

Kushlan, J.A. 1987. External threats and internal management: the hydrologic regulation of the Everglades. Environmental Management 11:109-119.

Kushlan, J.A. and F. Mazzotti. 1989. Population biology of the American crocodile. Journal of Herpetology 23:7-21.

Kushlan, J.A. and F. Mazzotti. 1989. Historic and present distribution of the American crocodile in Florida. Journal of Herpetology 23:1-7.

Kushlan, J.A. 1992. Population biology and conservation of colonial wading birds. Colonial Waterbirds 15:1-7.

Kushlan, J.A. 1993. Waterbirds as bioindicators of wetland change: Are they a valuable tool? Pp. 48-55. In: Waterfowl and Wetland Conservation in the 1990s – a global perspective. (M. Moser, R.C. Prentice, and J. Van Vessem, eds.), IWRB Special Publication No. 26. Slimbridge, UK.

Kushlan, J.A. 1993. Colonial waterbirds as bioindicators of environmental change. Colonial Waterbirds 16:223-251.

Kushlan, J.A. 1997. Water regimes and principles for management of wetland systems. Pp. 27-35. In: Wetlands and Watershed Management: Science, Applications and Public Policy, (J. Kusler, D. E. Willard, and H. C. Ellis, eds.). Association of State Wetland Managers, Berne, NY, USA.

Kushlan, J.A. 2011. Heron count protocols:  Inventory, census and monitoring of herons. HeronConservation, www.HeronConservation.org.