the herons
DESCRIPTION
The Herons. Family Ardeidae. Michael Bennett. Systematics. Kingdom: Animalia. Phylum: Chordata. Class: Aves. Order: Ciconiiformes. Family: Ardeidae. Genus: Ardea Butorides Nycticorax Nyctanassa. Long, S-shaped neck. Heavy, pointed bills. Slender legs. - PowerPoint PPT PresentationTRANSCRIPT
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Ciconiiformes
Family: Ardeidae
Genus: Ardea Butorides Nycticorax Nyctanassa
Systematics
Heron Life History Traits
Nest In Trees -Rarely on ground
-Rarely far from water
2 – 6 pale blue eggs
Mostly Colonial
Complex Breeding Displays
Territorial esp. in breeding season
Heron Life History Traits Cont.
Piracy is Common
Diet primarily fish -Also invertebrates, insects,and rodents
Forage by wading/stalking
Seasonally monogamous -Most breed second year
Both sexes care for young-Altricial young
Populations Then and Now Cont.
Increases in 1950’s
Most pop. stable or increasing
-Habitat protection and restoration
-Beaver protection
Heron Diversity
App. 65 species in Ardeidae - With argument and more to come - 13 species in N. America
Family divided into four groups (Payne & Risley 1976)
Night HeronsDay Herons
BitternsTiger Herons
Heron Diversity Cont.Herons are present on every continent (except Antarctica) -Highest diversity in Central and South America
Herons in Kentucky
Four occur in Kentucky
Yellow-Crowned Night Heron
Black-Crowned Night Heron
Great Blue Heron
Green Heron
The Yellow-Crowned Night Heron
Nyctanassa violacea
Summer
Winter
Range maps courtesy of USGS CBC/BBS
Nocturnal/Crepuscular
Relatively Selective
Yellow crown
Obvious head plumes
White face patch
Prefers forested wetlands
Black-Crowned Night Heron Black cap
Short neck
Single plume
Red eye
Nycticorax nycticorax
Primarily Nocturnal
Cosmopolitan(except Australia)
Prefers swamps/marshes
Often nests with other species
Black-Crowned Range
summer
winter
Range maps courtesy of USGS CBC/BBS
Found throughout N.A.
Range seems to be expanding(Based on CBC/BBS)
Found in W. Kentucky
Winters into Central America
Great Blue Heron Intro.Blue Heron Intro.
-Largest heron in N.A.
-Wide spread and common
-Most widely studied heron
-Many subspecies
- Up to 20 in the past
- Currently around seven
-Great white most obvious subspecies
Ardea herodias
Identification
Black shoulder patch
Occipital plumes (Not always obvious)
Bluish-grey in color
Grey heron is similar but lives in Europe/Africa
Identification Cont.Ardea herodias occidentalis
- Entirely White
- Larger than Egrets
- Great White Heron
Breeding and NestingFresh & brackish water
Most often in marsh/swamp - prefers trees
Male collects material, female builds nest
Breeding and Nesting Cont.Highly territorial when nesting
Nest defense by both sexes
Bill fencing common
Many courtship/defense displays
Eggs and YoungTwo – six eggs
-Increases with latitude
Semi-altricial young
-Eyes open, has down
Both parents brood/feed young
Fledge around 80 days-Varies with latitude
Eggs and Young Cont.• Adults tend young up to 3
weeks after fledge
• Foraging skill increases with age (Butler 1991)
• Most breed in second spring• Rarely return to natal site
Management Concerns
Highly adaptable to varying habitat(Powell et al. 1981)
Habitat Loss
-Cont. restoration/protection esp. pacific coastal
Will abandon if disturbed -Less likely later in incubation
-appropriate measure limit this
-Butler 1992 recommends 300m buffer
Will adapt to human presents
Management Concerns Cont.• Shootings common in past
• Federally protected
• Attitudes have changed
• Varity of control methods
• Netting most effective
• Pesticides effect success(ddt/dde)• Levels currently dropping• Home use is a problem• Better testing of chemical pesticides
and herbicides is needed
Green Heron IntroOne of the smallest herons
Most common heron in it’s range (and possibly N.A.)
Undergone many taxonomic and name changes
Green-backed heron
Blue-backed heron
Little green heron
Butorides virescens
Identification Cont.Juveniles Can be confused with American/Least Bittern
Least Bittern
American Bittern
Green Heron
Larger than least
Smaller than American
Green Heron Range
Map courtesy of Cornell Ornithological Laboratory
As far south as Ecuador
As far north as Vancouver
Common breeder in Ky
Habitat and Foraging
Stand still or stalks prey
More likely to inhabit streams
Typically Grabs rather spears prey
One of the few tool using birds
• Usually solitary nester• Will nest in loose colonies
• Seasonally monogamous• Aerial and non-aerial breeding
displays • Includes vocalizations
• Territorial (less so than others)
• Male selects nest site and begins construction• Female finishes nest while male brings
material
Breeding and Nesting
Eggs and Young• Clutch size 3 – 5
• Both parents incubate• “relief ceremony” when
switching• Includes bill rubbing
and preening
• Can be multi-brooded in southern range
• Fledge in 16 days• Flightless until 21st day
Eggs and Young• Young swim well after
fledging• Est. 30-35 days until
independent of parents (Davis & Kushlan 1994)
• 1 – 2 yrs until first breeding
Management Concerns• Habitat loss
• Esp. ephemeral wetlands• Identification of semi-permanent wetland essential
• Often shot (more so in the past)• Considered a pest at fish hatcheries• Current regulations limit lethal control measures
• River usage • Limits heron usage• Can lead to nest failures • Underscores the need to protect smaller inaccessible
wetlands
Herons are diverse and complex group that span the globe
Their future health depends primarily on habitat protection and restoration
Much more research is needed in the fields of:Post fledgling survival
Habitat usesPopulation dynamicsEffects of disturbance