Illinois Natural History Survey - University of Illinois

Black-crowned night-heron
Nycticorax nycticorax

 

Taxonomy
Occurence in Illinois
Status
Habitat associations
Guilds
Food-habits
Environmental associations
Life history
Management practices
References


TAXONOMY

 

  • Phylum: Chordata
  • Class: Aves
  • Order: Ciconiiformes
  • Family: Ardeidae
  • Genus: Nycticorax
  • Species: Nycticorax nycticorax
  • Authority: Linnaeus

Comments on taxonomy:
Tribe: Nycticoracini *16*. Subspecies: N.n. hoactli (Gmelin); 4 subspecies, only N.n. hoactli present in North America *04*. Other names: American night heron; night heron; quawk; quok; squawk; qua- bird; mid-west, night raven, lake owl; Ga., red eye; Fla., night scrooglin, gobly-gossit, indian hen *05,07,13*.

 


OCCURENCE IN ILLINOIS

The black-crowned night-heron occurs in Illinois from early April- late October. It is a fairly common migrant and uncommon summer resident. Also a rare winter resident. Recent breeding accounts: 1982/83; over 500 nests at Pontoon Beach County; 177 nests at Barrington; 148 nests at Clear Lake; Lake Calumet, 55 nests *17*.

 


STATUS

Items in bold indicate applicable categories
Forest Service Categories: S = recommended for regional sensitive status, F = forest listed species, M = management indicator species

Federal Status:

Endangered Threatened Proposed for listing
Candidate for proposal Recovery plan approved Recovery plan received (USFWS)
Recovery plan in preparation Under notice of review Delisted
Migratory EPA indicator Forest Serv.- Shawnee species (F)

State Status:

Endangered Threatened Proposed

Other:

Game Furbearer Nongame protected
Sportfish Commercial Pest None of the above

Comments on status:
The black-crowned night-heron has shown a dramatic history of decline with only 4 sizeable colonies remaining in Illinois *01*. This species was placed on the Illinois endangered species list in 1977 and remains qualified for inclusion because of a) past history of decline b) small population numbers, and c) essential habitats are being threatened *01*. This species is also protected under the Migratory Bird Treaty Act of 1918 and the Illinois Wildlife Code of 1971 *19,22*.

 


HABITAT ASSOCIATIONS

Items in bold indicate applicable categories

General habitat:

Unknown Terrestrial Aquatic Riparian

USFS timber inventory forest size class:

Unknown Unstocked Seedling Sapling
Seedling/sapling Pole Mature Over mature

Land use and land cover:

Unknown   Urban Residential
Commercial
Industrial
Transportation, communication
Complex industrial/commercial
Mixed
Other
Agricultural Crop, pasture
Orchards, groves, nurseries
Feedlot
Other
Rangeland Herbaceous
Shrub and brush
Mixed
Forestland Deciduous
Evergreen
Mixed
Water Stream
Lake
Reservoir
Bay
Wetland Forest
Non-forest
Barren Salt flat
Beach
Sand
Rock
Mine
Transit
Mix

 


Forest cover types:

Cover typeStructural stageCanopy closureSeason
All All Unknown Unknown

Associated tree species:

  • Willow

National wetland inventory classifications:

SystemSubsystemClassSubclassWater regime modifiersWater chemistry
Lacustrine Littoral Emergent vegetation Persistent Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Emergent vegetation Nonpersistent Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Flat Mud Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Forest Deciduous Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Forest Evergreen Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Scrub/shrub Deciduous Intermittently exposed/permanent nontidal Freshwater
Lacustrine Littoral Scrub/shrub Evergreen Intermittently exposed/permanent nontidal Freshwater
Palustrine   Emergent vegetation Persistent Intermittently exposed/permanent nontidal Freshwater
Palustrine   Emergent vegetation Nonpersistent Intermittently exposed/permanent nontidal Freshwater
Palustrine   Flat Mud Intermittently exposed/permanent nontidal Freshwater
Palustrine   Forest Dead trees Intermittently exposed/permanent nontidal Freshwater
Palustrine   Forest Deciduous Intermittently exposed/permanent nontidal Freshwater
Palustrine   Forest Evergreen Intermittently exposed/permanent nontidal Freshwater
Palustrine   Scrub/shrub Deciduous Intermittently exposed/permanent nontidal Freshwater
Palustrine   Scrub/shrub Evergreen Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Emergent vegetation Persistent Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Emergent vegetation Nonpersistent Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Flat Mud Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Forest Deciduous Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Forest Evergreen Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Scrub/shrub Deciduous Intermittently exposed/permanent nontidal Freshwater
Riverine Lower perennial Scrub/shrub Evergreen Intermittently exposed/permanent nontidal Freshwater

Comments on species-habitat associations:
The black-crowned night-heron seems adapted to nearly every conceivable habitat in which a wading bird may exist *04*. This species depends on wetlands for food and is found near freshwater ponds, lakes, sluggish streams, swamps, marshes, backwaters and shallow lagoons *12,14*. The proximity of foraging areas might be the most important factor in nest site selection, therefore, black- crowned night-herons utilize a wide variety of upland and lowland tree species and where suitable tree species cannot be found they will often nest in marsh vegetation where their nests are concealed *03,05, 14*.

Important plant and animal association: Gizzard shad.
Gizzard shad seem to be the principal food item of this species (and other herons) in Illinois *03,04,14*.

High value habitats

HabitatStructural stageSeason
Forested wetland Special habitat Fall
Forested wetland Special habitat Spring/summer
Nonforested wetland Special habitat Fall
Nonforested wetland Special habitat Spring/summer
Wet-mesic upland forest All Fall
Wet-mesic upland forest All Spring/summer
Floodplain forest All Fall
Floodplain forest All Spring/summer
Wetland Special habitat Fall
Wetland Special habitat Spring/summer
Marsh Special habitat Fall
Marsh Special habitat Spring/summer
Swamp Special habitat Fall
Swamp Special habitat Spring/summer
Shrub swamp Special habitat Fall
Shrub swamp Special habitat Spring/summer
Lakes and ponds Not applicable
(HVAL-HAB cover)
Fall
Lakes and ponds Not applicable
(HVAL-HAB cover)
Spring/summer
Streams Special habitat Fall
Streams Special habitat Spring/summer
Marsh restoration Special habitat Fall
Marsh restoration Special habitat Spring/summer

Species-habitat interrelations: 1) Wetlands, foraging sites, high, spring/summer/fall *01,12,14*.
2) Bottomland forest, forested wetlands, nesting sites, high, spring/summer *01,04*.
The black-crowned night-heron's nesting sites are so varied, as to suggest the quality and proximity of foraging areas might be the most important factor in nest site selection *01,03,14*. Thus, this species frequents areas such as lagoons, backwaters, marshes, swamps, ponds, lakes, sluggish streams and rivers to secure a foraging site, consequently nesting in best available situation *01,03,05,07,13,14*.

 


GUILDS

Feed-guilding:

HabitatStructural stageSeasonFeed-guilds
Wetland Special habitat All Water bottom-unconsolidated bottom, arthropods
Water bottom-aquatic bed, arthropods
Water column- arthropods
Water surface- arthropods
Water bottom-unconsolidated bottom, invertebrates other than zooplankton or arthropods
Water bottom-aquatic bed, invertebrates other than zooplankton or arthropods
Water column- invertebrates other than zooplankton or arthropods
Water surface- invertebrates other than zooplankton or arthropods
Water bottom-unconsolidated bottom, fish
Water bottom-aquatic bed, fish
Water column- fish
Water surface- fish
Water bottom-unconsolidated bottom, amphibians
Water bottom-aquatic bed, amphibians
Water column- amphibians
Water surface- amphibians
Water bottom-unconsolidated bottom, reptiles
Water bottom-aquatic bed, reptiles
Water column- reptiles
Water surface- reptiles
Wetland Special habitat All Terrestrial surface- arthropods
Terrestrial surface- invertebrates other than arthropods
Terrestrial surface- amphibians
Terrestrial surface- reptiles
Terrestrial surface- birds
Terrestrial surface- small mammals (< 1 kg)

Comments on feed-guilding:
The black-crowned night-heron is a wading bird that eats primarily fish and other aquatic life. This species is extremely adaptable and eats whatever is most plentiful at the time and place. It is also known to take young birds and small mammals (mice) *03,05,07*.

Breed-guilding:

HabitatStructural stageSeasonBreed-Guilds
Wetland Special habitat Spring/summer Terrestrial surface
Shrub strata, canopy of broad-leaved deciduous shrubs
Shrub strata, canopy of needle-leaved deciduous shrubs
Shrub strata, canopy of broad-leaved evergreen shrubs
Shrub strata, canopy of needle-leaved evergreen shrubs
Shrub strata, grass and grasslike vegetation extending into shrub strata
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees

Comments on breed-guilding:
The black-crowned night-heron usually copulates at or near its nest site *04*. Usually places nest in trees, shrubs, or marsh vegetation near accessable foraging areas *00,01,03,04*.

 


FOOD-HABITS

Trophic level is CARNIVORE

Food itemLife stage/plant part
Mollusca Unknown
Mollusca: Gastropoda (snails) Unkown
Arthropoda Unknown
Crustaceans Unknown
Malacostraca (isopods, amphipods, crayfishes) Unknown
Insecta Unknown
Odonata (dragonflies, damselflies) Adult
Odonata (dragonflies, damselflies) Nymph
Orthoptera (grasshoppers, crickets, cockroaches) Unknown
Osteichthyes (bony fishes) See comments
Semionotiformes (gars) See comments
Anguilliformes (American eel) See comments
Clupeiformes (herrings) See comments
Salmoniformes (trouts, salmons, smelts, pikes) See comments
Cypriniformes (carps, minnows, loaches) See comments
Perciformes (basses, sunfishes, perches, sculpins) See comments
Caudata (salamanders,newts,sirens,mudpuppies,hellbenders) Unknown
Salientia (frogs, toads) Juvenile
Salientia (frogs, toads) Adult
Testudines (turtles) Unknown
Sauria (lizards, skinks, iguana) Unknown
Serpentes (snakes) See comments
Mammals See comments
Cricetidae (woodrats, mice, voles, lemmings, muskrat) See comments
Ciconiiformes See comments
Passeriformes See comments
Important:
Osteichthyes (bony fishes) See comments
Clupeiformes (herrings) See comments
Cypriniformes (carps, minnows, loaches) See comments
Perciformes (basses, sunfishes, perches, sculpins) See comments
Caudata (salamanders,newts,sirens,mudpuppies,hellbenders) Unknown
Salientia (frogs, toads) Juvenile
Salientia (frogs, toads) Adult
Juvenile:
Osteichthyes (bony fishes) See comments
Clupeiformes (herrings) See comments
Cypriniformes (carps, minnows, loaches) See comments
Perciformes (basses, sunfishes, perches, sculpins) See comments
Caudata (salamanders,newts,sirens,mudpuppies,hellbenders) Unknown
Salientia (frogs, toads) Juvenile
Salientia (frogs, toads) Adult
Adult:
Mollusca Unknown
Mollusca: Gastropoda (snails) Unkown
Arthropoda Unknown
Crustaceans Unknown
Malacostraca (isopods, amphipods, crayfishes) Unknown
Insecta Unknown
Odonata (dragonflies, damselflies) Adult
Odonata (dragonflies, damselflies) Nymph
Orthoptera (grasshoppers, crickets, cockroaches) Unknown
Osteichthyes (bony fishes) See comments
Semionotiformes (gars) See comments
Anguilliformes (American eel) See comments
Clupeiformes (herrings) See comments
Salmoniformes (trouts, salmons, smelts, pikes) See comments
Cypriniformes (carps, minnows, loaches) See comments
Perciformes (basses, sunfishes, perches, sculpins) See comments
Caudata (salamanders,newts,sirens,mudpuppies,hellbenders) Unknown
Salientia (frogs, toads) Juvenile
Salientia (frogs, toads) Adult
Testudines (turtles) Unknown
Sauria (lizards, skinks, iguana) Unknown
Serpentes (snakes) See comments
Mammals See comments
Cricetidae (woodrats, mice, voles, lemmings, muskrat) See comments
Ciconiiformes See comments
Passeriformes See comments

Comments on food habits: 
General: The most important food item for the black-crowned night-heron in Illinois seems to be small fishes primarily gizzard shad *03,14*. This species has been reported to take some algae and other succulent plants, but it is classified as pre-eminently carnivorous *05,12*. The black-crowned night-heron is extremely adaptable and eats whatever is most plentiful at the time and place *07*.
Juvenile: Juvenile food items seem identical to adult food items but are presented in different forms depending on age of young. At hatching, young are fed predigested juices and size of food increases with age of young *04,12*. See general or important food items.
Adult: See general or important food items.


ENVIRONMENTAL ASSOCIATIONS

General:

  • Biodegradable organics: clean waters that have not been polluted
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Flood plain: see comments
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Aquatic habitats: mud flats
  • Aquatic habitats: vegetated streambank
  • Aquatic habitats: island inhabitant
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: swamp
  • Aquatic habitats: marsh
  • Aquatic habitats: oxbow
  • Aquatic habitats: backwaters
  • Ecotones: woodland/water
  • Orchards: see comments
  • Pastures: see comments
  • Shrubs: see comments
  • Vines: see comments
  • Coniferous forest: see comments
  • Hardwood forest: see comments
  • Human associations: public city parks
  • Human associations: wildlife refuges/sanctuaries
  • Unknown

Limiting:

  • Biodegradable organics: clean waters that have not been polluted
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Flood plain: see comments
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: swamp
  • Aquatic habitats: marsh

Egg

  • Unknown

Feeding juvenile:

  • Biodegradable organics: clean waters that have not been polluted
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Aquatic habitats: mud flats
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: swamp
  • Aquatic habitats: marsh
  • Aquatic habitats: oxbow
  • Aquatic habitats: backwaters

Resting juvenile:

  • Flood plain: see comments
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Shrubs: see comments
  • Vines: see comments
  • Coniferous forest: see comments
  • Hardwood forest: see comments

Feeding adult:

  • Biodegradable organics: clean waters that have not been polluted
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Aquatic habitats: mud flats
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: swamp
  • Aquatic habitats: marsh
  • Aquatic habitats: oxbow
  • Aquatic habitats: backwaters

Resting adult:

  • Flood plain: see comments
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Shrubs: see comments
  • Vines: see comments
  • Coniferous forest: see comments
  • Hardwood forest: see comments

Breeding adult:

  • Biodegradable organics: clean waters that have not been polluted
  • Aquatic habitat: shallows with emergent vegetation (littoral zone)
  • Flood plain: see comments
  • Aquatic habitats: typha-scirpus marsh
  • Aquatic habitats: freshwater marsh
  • Aquatic habitats: sloughs, bayous
  • Aquatic habitats: swamp
  • Aquatic habitats: marsh
  • Aquatic habitats: oxbow
  • Aquatic habitats: backwaters

Comments on environmental associations:
General: Foraging areas appear more critical to the black-crowned night-heron than nest sites *01*. Unpolluted and undisturbed wetlands are essential as foraging areas and considering the adaptability of this species it can nest in a variety of situations *01,03,04,14*.
Feeding juvenile: Nestlings are fed in the nest and assumed to adopt adult feeding habits when fledged. See environmental assoc. for feeding adult *00*.
Resting juvenile: Juveniles initially rest in nest and near nest site after fledging. They then move to roost trees with adults. Since this species is highly variable in the placement of its nest, resting areas may be located from near ground, in shrubs, vines, to a variety of tree species *03,04,05,13*.
Feeding adult: Unpolluted, undisturbed wetlands are essential as foraging areas *01,03*.
Resting adult: Adults may rest near nest site and in roost trees *07*. Due to highly variable nest placement this species may rest in a variety of shrubs, vines and trees, etc. *04*.
Breeding adult: See species environmental associations and limiting factors. Also stability was seemingly critical to the selection of nest sites in North Carolina, Massachusetts and Virginia *08*. Birds will nest in any available vegetation that will support a nest *08*.


LIFE HISTORY

Origin: Native *02*.

Physical description: 23-28 ins. in length; 45 in. wingspread. Sexes are outwardly similar but males average larger. Body is heavy, chunky; short thick neck, short legs and heavy bill. Adults: head with black cap, short crest. 2-3 Narrow white plumes at back of head. Eyes scarlet, back black, underparts white, wings and tail gray. Immature: brown streaked or spotted with white *04,07,21*.

Reproduction: The black-crowned night-heron is seasonally monogamous *04*. It is a colonial nester often nesting with other heron species, but also nests singly *03*. It is reported that Illinois birds go directly to their nesting colonies as they return from wintering *03*, but palmer (1962) states there is a definite delay before the occupying of nesting territory *04*. Courtship and mating are not described for Illinois *03*. Palmer (1962) reports both sexes arrive at approx. the same time. After a delay the male selects a territory and begins to display. As with the snowy egret the displaying male attracts a crowd, eventually letting 1 female in to nest *04,07*. Courtship is simple and once pair bond is formed it is maintained through the greeting display, billing and feather nibbling *04*. If the male chooses a territory containing an old nest the pair may rework this by adding new material. Typically the male brings the female sticks/twigs and she does the actual construction *04*. Unlike other heron species the male black-crowned night-heron rarely finishes the foundation (of a new nest) prior to pair formation *04*. The nest site of the black-crowned night-heron is highly variable ranging from ground level to over 160 ft. in a wide variety of upland and lowland trees, shrubs or aquatic vegetation *03,04,05*. This species will nest in any available vegetation that will support a nest *08*. The quality and proximity of foraging areas might be the most important factor in nest site selection *14*. Building material varies with habitat but generally consists of sticks/twigs or stems *04,07*. In New England it usually takes 2-5 days sometimes 7 days to complete nest construction *04, 05*. Copulation takes place in or near nest site and is typically preceeded by a greeting ceremony. Copulation usually occurs on 1st or 2nd day after pair formation. Duration averages 12 (8-17) seconds *04*. The first egg is layed on ave. 3.3 days after first copulation and 4-5 days after pair formation *04*. Nesting begins: Florida (Dec.); Georgia (mid Apr.); South Carolina (mid-late Apr.); New Jersey (early Apr.); New York (mid Apr.); Michigan (late Apr.-early May); Minnesota (late Apr.) *04*. Egg dates; north and central Illinois (24 Apr.-18 June); New England (May 13-20); California (May 3-23); New Jersey and Pennsylvania (Apr. 10-June 12); Florida (March 1-Apr. 17) *03,05*. Clutch size averages 3-5 (1-6) and rarely 7 or 8 eggs. The larger sets may be the product of 2 birds *04*. Mean clutch size apparently increases as move northward within the species range *08*. Mean clutch size also decreases as the season progresses. Apparently late nesters are usually young birds nesting for the first time and older individuals lay larger clutches *08*. Eggs are pale green-blue, 53 x 37 mm., and are apparently layed at 2 day intervals *03,04,05*. Incubation begins with the first egg and continues for 24-26 days. Both sexes incubate *04,05,07*. Upon hatching, young are partially covered with gray down with long whitish filaments on the crown *05*. The first day after hatching the young are fed pre-digested juices which are delivered into their open mouths *04,05*. After 3 days feeding consists of dropping larger pieces onto the floor or the rim of the nest and when older the young grab the parents bill in typical heron fashion *04,05*. Weights are approximately: 24.2 gm (1 day); 93.5 gm (5 days); 249.5 (10 Days); 598 gm (28 days) and 935 gm (44 days) *04,13*. First flight occurs at approximately 6 weeks usually to pursue adults to feeding areas to beg for food *04*. Young birds assume full adult plumage at approx. 2 1/2 years *05*. First year individuals were observed breeding in Rhode Island and New England but most usually not until 2-3 years *04,08,13*.

Behavior: The black-crowned night-heron is migratory spending from early Apr.-late Oct. in Illinois. This species breeds from Washington, Saskatchewan, Minnesota and New Brunswick south to South America and winters in the warmer parts of its range *01*. It is territorial on both nesting and feeding grounds *04*. On breeding grounds the male selects a territory that is used for hostile and sexual displays, copulation and nesting *04*. As with other heron species, initial territory of the male is larger than subsequent territory held by mated pair, which is little more than a few feet around nest *04*. The black-crowned night-heron engages in ritualized displays for threat, defense, and courtship *04*. The black-crowned night-heron is highly social and usually nests with other heron species, especially the great blue heron and great egret *04*. This species seems adapted to every conceivable habitat in which a wader may exist and it appears nest site selection revolves around the quality and proximity of foraging areas *14*. The black-crowned night-heron is an expert still-fisherman but also stalks its prey. Its periods of greatest activity are from dawn to sunrise and dusk until dark *05*. It is largely but not strictly nocturnal and sometimes feeds during daytime *07*. Most daylight hours are spent roosting in trees *07*. As in other herons, the black-crowned night-heron experiences a post-breeding dispersal, usually being the young birds that indulge in these erratic movements *03,04,05*. Northward flights begin in august soon after nesting is completed *03*. How soon southward flights begin is not known but suspect migration back through Illinois takes place Sept.- Oct. *03*. Though most of the population is south of Illinois by October there are enough Nov., Dec., and Jan. records to suggest that a few individuals linger, perhaps regularly *03*. The lack of Feb. records may mean poor winter survival or just a paucity of observers *03*.

Limiting factors: Population size for Illinois is not known but only 4 sizeable breeding colonies remain *03,17*. Numbers have been reduced in many localities by land clearing, drainage, lumbering, and development *01,04*. Black-crowned night-herons are susceptible to pollution. The presence of organochlorines and heavy metals are present in eggs taken from Mass., N.J., M.Y., Md., R.I., Conn., Va., N.C., S.C., Fla., Ga., Ohio, Mich., Wisc., and Minn. *18*. This study could not positively relate residues to declines of night-heron populations but circumstantial evidence suggests that environmental pollutants may contribute to impaired reproductive success in the more contaminated areas *18*. Enemies include raccoons, crows, hawks, vultures, skunks, weasels and foxes *05, 10,13*. Black-crowned night-herons are particularly sensitive to disturbance just before and during laying *06*. In Quebec, disturbance reduced nesting success by inhibiting laying, increasing either nest abandonment or egg predation and increased nestling mortality *06*. The filling and draining of wetlands and continued use of persistent pesticides reduce viable foraging areas that are essential to this species *19*. Preservation and proper care of both nesting and foraging areas are critical and human encroachment during breeding season should be eliminated in order to prevent decreased nesting success *01*.

Population parameters: The relative trend for the black-crowned night- heron in Illinois is not known. Only 4 sizeable extant colonies: Pontoon Beach, Barrington, Clear Lake and Lake Calumet remain in 1983 and all are associated with areas that still have marshes near by *03,17*. Mortality rates have been reported as 61% for 1st year birds and 31% in older birds (after 2nd August of life) *12*. In Georgia nesting success was reported to be 87%, percent eggs that were successful was 71% *22*. Nesting success for Long Island was 100% with 94% eggs hatching. In Maryland, Virginia and North Carolina hatching success was 77.2% with 91.4% of hatchlings living through their 15th day *08*. 1 Estimate for productivity was made for Illinois. Neal (1976) found 3.3 young per nest in Waukegan *03*. Henney (1972) estimated 2.0-2.1 night-heron young had to fledge per nesting female to maintain a stable population *08*. No recent data is available. Black-crowned night-herons are reported to be stable or increasing their numbers in Massachusetts, Rhode Island, and Long Island *08*. No sex ratios are reported for Illinois. Average age of black-crowned night-herons is approx. 2 years 11 months and the oldest bird was found in Ohio at 21 years 1 month, for Illinois the oldest bird is just over 14 yrs. *12*. Life expectancy is 1.8 years and after the first year of life it increases to 2.7 years *12*.

 


MANAGEMENT PRACTICES

Beneficial:

  • Maintaining undisturbed/undeveloped areas
  • Maintaining natural areas and nature preserves
  • Maintaining unique or special habitat features (wetlands, snags, caves, cliffs, talises, etc.
  • Preserving endangered species habitat
  • Preserving sensitive species habitat
  • Performing special survey prior to prescription
  • Performing field survey prior to prescription
  • Controlling land use and human activities
  • Seasonal restriction of human use of habitats
  • Controlling pollution
  • Controlling pollution in aquatic habitats
  • Maintaining streams
  • Developing/maintaining lakes and ponds
  • Developing/maintaining wetlands
  • Creating/maintaining wetlands from non-wetlands
  • Developing/maintaining mudflats
  • Protecting existing wetlands
  • Restoration of wetlands (return flooded or drained areas to previous wetland conditions)
  • Developing/maintaining riparian habitat
  • Restricting human disturbance during migration, breeding, and nesting

Adverse:

  • Channelization
  • Dredging
  • Draining ponds/lakes
  • Draining wetlands
  • Applying pesticide on agricultural land
  • Strip mining
  • Applying pesticides
  • Cutting and deforestation

Existing:

  • Performing special survey prior to prescription

Comments on management practices:
The filling and draining of wetlands and continued use of persistent pesticides constitute a serious threat to all wading birds *19*. The preservation and proper care of both nesting and foraging sites is critical to the black-crowned night-heron's continuation as a breeding bird in Illinois *01*. Sanctuaries are the best means of preserving habitat *19*. It is also important to locate extant colonies and protect them *03*. Human encroachment during the breeding season should be eliminated to prevent nest abandonment *01*. The black- crowned night-heron is protected as an endangered species in Illinois, by the Migratory Bird Treaty Act of 1918 and the Illinois Wildlife Code 1897 *01,19,22*.

 


REFERENCES

0. MALMBORG, PATTI L. ILL. NAT. HIST. SURV., 607 E. PEABODY DR., CHAMPAIGN, ILL. 61820 (217)333-6846.

1. BOWLES, M. 1981. ENDANGERED AND THREATENED VERTEBRATE ANIMALS AND VASCULAR PLANTS OF ILLINOIS. ILL. DEPT. OF CONS. PG. 38.

2. BOHLEN, H.D. 1978. AN ANNOTATED CHECK-LIST OF THE BIRDS OF ILLINOIS. ILL. STATE MUS., POP. SCI. SER. VOL. IX. PG. 20.

3. GRABER, J.W., R.R. GRABER, E.L. KIRK. 1978. ILLINOIS BIRDS: CICONIIFORMES. BIOLOGICAL NOTES NO. 109. I.N.H.S. URBANA. PG. 51- 61.

4. PALMER, R.S. 1962. HANDBOOK OF NORTH AMERICAN BIRDS. VOL. 1. YALE UNIV. PRESS, NEW HAVEN. P. 472.

5. BENT, A.C. 1926. LIFE HISTORIES OF NORTH AMERICAN MARSH BIRDS. U.S. NATL. MUS. BULL. NO. 135. PP. 197-213.

6. TREMBLAY, J. & L. ELLISON. 1979. EFFECTS OF HUMAN DISTURBANCE ON BREEDING OF BLACK-CROWNED NIGHT HERONS. AUK 96:364-369.

7. TERRES, J.K. 1980. THE AUDUBON SOCIETY ENCYCLOPEDIA OF NORTH AMERICAN BIRDS. ALFRED A. KNOPF. NEW YORK. P. 498.

8. CUSTER, T.W., G.L. HENSLER, AND T.E. KAISER. 1983. CLUTCH SIZE, REPRODUCTIVE SUCCESS, AND ORGANOCHLORINE CONTAMINANTS IN ATLANTIC COAST BLACK-CROWNED NIGHT-HERONS. AUK 100:699-710.

9. CUSTER, T.W., AND W.E. DAVIS. 1982. NESTING BY ONE-YEAR-OLD BLACK- CROWNED NIGHT HERONS ON HOPE ISLAND, RHODE ISLAND. AUK 99:784-786.

10. BURGER, J. 1977. CROW PREDATION ON BLACK-CROWNED NIGHT HERON EGGS. WILSON BULL. 89(2):350-351.

11. BEAVER, D.L., R.G. OSBORN, AND T.W. CUSTER. 1980. NEST-SITE AND COLONY CHARACTERISTICS OF WADING BIRDS IN SELECTED ATLANTIC COAST COLONIES. WILS. BULL. 92(2):200-220.

12. KAHL, M.P. 1963. MORTALITY OF COMMON EGRETS AND OTHER HERONS. AUK 80:295-300.

13. GROSS, A.O. 1923. THE BLACK-CROWNED NIGHT HERON (NYCTICORAY NYCTICORAX NAEVIUS) OF SANDY NECK. AUK 40(1):1-30.

14. ILLINOIS LAND REPORT:RICE LAKE CONSERVATION AREA. 1983. (EDS.) T. JOHNSON & W.N. BRIGHAM. VOL. I ILLINOIS DEPT. OF ENERGY & NAT. RES. SPRINGFIELD. DOC N LR 83/01 V-II P. 44.

15. KLEEN, V. 1982.83. FIELD NOTES:BREEDING SEASON. ILL. AUDUBON BULL. ILL. AUDUBON SOCIETY, WAYNE, IL. PG. 27.

16. 34TH SUPPLEMENT TO THE AMERICAN ORNITHOLOGIST'S UNIONS CHECK-LIST OF NORTH AMERICAN BIRDS. SUPPLEMENT TO AUK VOL. 99.

17. OHLENDORF, H.M, E.E. KLAAS, AND T.E. KAISER. 1978. ENVIRONMENTAL POLLUTANTS AND EGGSHELL THINNING IN THE BLACK-CROWNED NIGHT HERON. PP. 63-82 IN WADING BIRDS (EDS.) A. SPRUNT, J.C. OGDEN & S. WINCKLER. RES. REPT. NO. 7. NATIONAL AUDUBON SOCIETY, N.Y.

18. ANDERSON, J.M. 1978. PROTECTION AND MANAGEMENT OF WADING BIRDS. PP. 99-103 IN WADING BIRDS (EDS.) A. SPRUNT, J.C. OGDEN, & S. WINCKLER. RES. REPT. NO. 7. NATL. AUDUBON SOC. N.Y.

19. U.S. FISH AND WILDLIFE SERV. 1983. CODE OF FEDERAL REGULATIONS. TITLE 50. WILDLIFE AND FISHERIES. CHAPTER 1 PP. 11-18. 50 CFR 10.13. LIST OF MIGRATORY BIRDS. SPEC. PUBL. FEDERAL REGISTER. GENERAL SERV. ADMIN. OCT. 1.

20. PETERSON, R.T. 1980. A FIELD GUIDE TO THE BIRDS. HOUGHTON MIFFLIN, CO., BOSTON. P. 104.

21. TEAL, J.M. 1965. NESTING SUCCESS OF EGRETS AND HERONS IN GEORGIA. WILS. BULL. 77:257-263.

22. ILLINOIS DEPT. CONSERV. 1980. CONSERVATION LAWS. CH. 61, WILDLIFE ART. II. PAR 2.2. REPRINTED FROM ILLINOIS REVISED STATUTES, 1979. WEST PUBL. CO., ST. PAUL, MN. 123P.

 


 

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