North American Kestrel

Falco sparverius Order: Falconiformes Family: Falconidae

Overview

Males are easily distinguished from females by their size (males are smaller) and their slate blue wings (females have brown wings). Kestrels possess a pair of false eye spots, or ocelli, on the nape of their neck. These dark circles are thought to be a form of protective coloration because they look like watching eyes and may deter potential predators.

Their sharp talons are used to grab their prey while the hooked beak is used to tear the prey into ingestible pieces.

North American kestrels are 9 to 12 inches in length. They are the smallest of the North American falcons.

Kestrels lead solitary lives for most of the year. They can be seen perched on telephone poles or on wires over grassy expanses.

Natural History Information

Range and Habitat

Kestrels live throughout the United States and Canada in warm months, and the middle States into South America in the winter. Preferred habitat is open country, farmlands, forest edges, and cities.

Longevity

In the wild, kestrels can live up to 8 to 11 years, but typical longevity is usually 3-6 years. In human care, the oldest recorded animal reached 17 years of age.

Ecosystem Role

The main prey of kestrels are small rodents and insects, therefore, kestrels play an important role in keeping agricultural pest species in check.

Husbandry Information

Housing Requirements

  • Life Cycle Natural History Relevant Information 
    • Include relevant information on breeding, reproduction, growth and development that may require necessary housing modifications.
  • Temperature, Humidity, Light Cycles
    • Habitat-relevant natural history information here
  • Substrate
  • This species can be successfully managed on a variety of substrates, such as pea-gravel, sand, dirt, grass.
  • Social Housing/Colony Management
    • Behavioral/Breeding natural history information here
    • Note how this species may be socially housed at your facility, how unique identifiers are used to differentiate individuals (where necessary), if they are housed in same sex or mixed sex groups, mixed age groups or multi-generational groups, with conspecifics only, in interspecific setups, etc. Note space requirements for social housing compared to singly-housed animals
  • Other General Housing Requirements or Management information
    • Multiple perching options are necessary to maintain good foot health.
    • Space should meet minimum USFW standards.
    • Enclosure should be constructed with materials that reduce the possibility of damage to the feathers or to the bird itself (for example, bare wire mesh is less desirable than vertical bars or coated mesh).
    • Flight-capable individuals need flight exercise to maintain muscle mass.
    • A double door mew entrance is ideal for any bird of prey. This allows handlers to enter the enclosure safely and without incident.
    • San Francisco Zoo: Their kestrel is housed in a 10’ x 4’ walk-in aviary during the day, and in a 10.5’ x 6.5’ mew overnight (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

Diet Requirements

  • Diet in the Wild
    • Primary prey are small rodents and a variety of insects.
  •  Diet under human care
    • Chicks, quail, mice, ducklings, and Dallas Crown.
    • San Francisco Zoo: Their kestrel is fed a daily rotation of mouse, rat, rabbit, and chick; diet is supplemented with Vitahawk 1x/week. Insects such as crickets, mealworms, and waxworms are also offered daily as enrichment. 

Veterinary Concerns

  •  

Enrichment & Training

Enrichment

  • Behavioral Relevant Information
    • Raptors seize and rip apart their prey. Offering whole prey items, shreddable enrichment items, items they can grab and manipulate with their talons or shred with their beaks are all good forms of enrichment. 
  • Environmental Enrichment 
    • Changing perches within their habitat.
    • Addition of browse. 
  • Behavioral Enrichment 
    • The most successful enrichment devices appear to be items that can be footed and shredded, such as paper products, cardboard boxes, lettuce, melons, squash or other produce. These items can be provided alone or stuffed with prey or diet, although raptors should be monitored for ingestion of foreign objects if food is delivered with a novel item. Other successful items include tennis balls, holl-ee rollers, and canvas dog toys, which present opportunities for seizing, grabbing, mock “killing,” and mantling.
    • San Francisco Zoo: Their kestrel is offered enrichment daily; items include cardboard boxes/tubes, paper bags, various substrates (i.e. Carefresh bedding, aspen shavings, newspaper), balls, ice treats, Kongs, puzzle feeders, corn husks, plastic toys.
  • Schedule 
    • Daily enrichment is recommended. 
  • Other Enrichment Resources 
    • AZA’s Raptor TAG has a comprehensive list of raptor-appropriate enrichment as well as other suggestions on raptor enrichment programs on their website.

Training

  • Behaviors Trained
    • Note any behaviors this species is trained for, both for husbandry, crating/transport, or for programming. 
    • Can the public participate in any trained behaviors?
    • San Francisco Zoo: Their kestrel is trained in the following behaviors:
      • Voluntary step-up/step-down
      • Voluntary weight 
      • A → B flights between trainers, perches, and platforms
      • Hover
      • Voluntary application/removal of equipment (anklets stay on, but jesses are put on/removed; anklets are made from kangaroo leather with size 00 grommet; jesses are small braided from Northwoods Falconry)
      • Voluntary nail trim (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

  • Reinforcers used & schedule of reinforcement 
    • Using food and/or weight management as part of a good behavioral management program facilitates training by creating a learning environment in which birds want to participate. Training strategies that involve reducing food offered to the point of compromising the health of the bird are considered unacceptable. Food management and weight management practices that are safe for the bird and trainers, provide for the health and welfare of the bird, and facilitate training are recommended. 
  • Food and or weight management should be done with an understanding of the process and considerations. The decision to use weight management should not be taken lightly nor undertaken at all by staff who do not have a comprehensive understanding of managing weight and diet. 

Other

Colony or Breeding Management

  • Note if species is housed or managed socially or for breeding purposes.

Individual Identification

  • Dimorphism or practiced ways to individually mark species (such as those in colonies, like giant millipedes).

Programmatic Information

Messaging Themes

  •  This species is in decline across North America, though a pinpoint cause has yet to be determined.

Threats and Conservation Status

  • American Kestrels are not listed as endangered, due to their widespread range from North to South America, but their numbers are declining, and in some regions have dropped more than 88% since the 1960s, such as the Mid-Atlantic. While no cause has been pinpointed, this may be due to the use of pesticides, loss of hunting and nesting habitat, climate change, exposure to new zoonotic diseases (such as Avian Influenza and West Nile) and human encroachment. Though often cited, some have thought that increased predation from Cooper’s Hawks may have contributed to their decline, but this has since been refuted.
  • Prejudices against birds of prey still persist among many who wrongly believe that they harm wildlife or present major threats to domestic animals. Biological studies have documented their ecological importance as major controls on rodent populations. Some birds of prey feed on snakes, insects or other potential pests. No species of raptor poses a significant threat to domestic animals.
  • Instruct guests to never litter, especially when they are in a car. Throwing trash out along the roads not only makes the roads less attractive, but can also attract animals to the sides of the road. Some of these animals might look appetizing to an owl, hawk, or other predator which are then more likely to be hit by passing vehicles.
  • For more information, check out the Peregrine Fund’s American Kestrel Partnership and the Brandywine Zoo’s Delaware Kestrel Partnership.

Interesting Natural History Information

Did you know…

  • Kestrels are able to hover in the air while using their keen eyesight to search the ground below for prey.
  • Kestrels can see in the ultraviolet spectrum which allows them to locate fresh urine trails from rodents on the move
  • Like other birds of prey, falcons ingest all of the prey animal, and later regurgitate the less digestible parts into a small pellet. This is called “casting a pellet.”
  • Falcons can be distinguished from hawks by their long, tapered wings.

Handling & Presentation Tips

  •  

Use Guidelines

  • This species may be presented on glove, on perch, or in free-flight demonstrations. For tethered presentation, whether that is to the glove or to a perch, attention should be paid to avoid bating. Bating is not something that should be accepted from hawks, if there are instances of such, it is an indication of discomfort, with the handler or the situation, and that discomfort should be addressed, not ignored.
  • San Francisco Zoo: Their kestrel is presented in the following ways:
    • On hand with equipment
    • Free-flighted without equipment in enclosed spaces (i.e. classrooms, aviary)
    • In small bird aviary (transported to aviary in kennel)
    • On creance in open spaces (i.e. Wildlife Theatre) (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

Pubic Contact and Interaction Guidelines

  • Public contact with this species is not advisable. 
  • Touching is not advisable.

Transportation Tips

  • Transport box suggestions Raptor Rig and Varikennel.
  • A couple things to keep in mind, crates should not be carried by the handle, but rather using two hands on either side of the crate and supporting it adequately. Swinging transport crates around and or moving them on a bumpy cart may create negative association for the bird, due to an uncomfortable ride and decrease the likelihood that the bird will go in the box on future occasions. If the perch is too low for the bird, their tail feathers may get painted with fecal matter which does not look good on presentation. 
  • San Francisco Zoo: Their kestrel is transported in a small Petmate Vari Kennel with installed perch and Astroturf lining

Crating Techniques

  • This species can be trained to voluntarily enter a crate either from the glove or directly from their enclosure. Continuous reinforcement of voluntary crate behaviors as well as dedication to their comfort and safety while in the crate is important to maintaining solid and reliable crate behavior.

Temperature Guidelines

  •  What temperature ranges can this animal be used outdoors? Any restrictions for travel that are temperature specific? How long can they be used at each temperature?

Acquisition Information

  • American kestrels are frequently available through rehabilitation organizations


Resources

Contributors and Citations

  • The Philadelphia Zoo
  • The Brandywine Zoo
  • San Francisco Zoo

Falco sparverius Order: Falconiformes Family: Falconidae

Overview

Males are easily distinguished from females by their size (males are smaller) and their slate blue wings (females have brown wings). Kestrels possess a pair of false eye spots, or ocelli, on the nape of their neck. These dark circles are thought to be a form of protective coloration because they look like watching eyes and may deter potential predators.

Their sharp talons are used to grab their prey while the hooked beak is used to tear the prey into ingestible pieces.

North American kestrels are 9 to 12 inches in length. They are the smallest of the North American falcons.

Kestrels lead solitary lives for most of the year. They can be seen perched on telephone poles or on wires over grassy expanses.

Natural History Information

Range and Habitat

Kestrels live throughout the United States and Canada in warm months, and the middle States into South America in the winter. Preferred habitat is open country, farmlands, forest edges, and cities.

Longevity

In the wild, kestrels can live up to 8 to 11 years, but typical longevity is usually 3-6 years. In human care, the oldest recorded animal reached 17 years of age.

Ecosystem Role

The main prey of kestrels are small rodents and insects, therefore, kestrels play an important role in keeping agricultural pest species in check.

Husbandry Information

Housing Requirements

  • Life Cycle Natural History Relevant Information 
    • Include relevant information on breeding, reproduction, growth and development that may require necessary housing modifications.
  • Temperature, Humidity, Light Cycles
    • Habitat-relevant natural history information here
  • Substrate
  • This species can be successfully managed on a variety of substrates, such as pea-gravel, sand, dirt, grass.
  • Social Housing/Colony Management
    • Behavioral/Breeding natural history information here
    • Note how this species may be socially housed at your facility, how unique identifiers are used to differentiate individuals (where necessary), if they are housed in same sex or mixed sex groups, mixed age groups or multi-generational groups, with conspecifics only, in interspecific setups, etc. Note space requirements for social housing compared to singly-housed animals
  • Other General Housing Requirements or Management information
    • Multiple perching options are necessary to maintain good foot health.
    • Space should meet minimum USFW standards.
    • Enclosure should be constructed with materials that reduce the possibility of damage to the feathers or to the bird itself (for example, bare wire mesh is less desirable than vertical bars or coated mesh).
    • Flight-capable individuals need flight exercise to maintain muscle mass.
    • A double door mew entrance is ideal for any bird of prey. This allows handlers to enter the enclosure safely and without incident.
    • San Francisco Zoo: Their kestrel is housed in a 10’ x 4’ walk-in aviary during the day, and in a 10.5’ x 6.5’ mew overnight (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

Diet Requirements

  • Diet in the Wild
    • Primary prey are small rodents and a variety of insects.
  •  Diet under human care
    • Chicks, quail, mice, ducklings, and Dallas Crown.
    • San Francisco Zoo: Their kestrel is fed a daily rotation of mouse, rat, rabbit, and chick; diet is supplemented with Vitahawk 1x/week. Insects such as crickets, mealworms, and waxworms are also offered daily as enrichment. 

Veterinary Concerns

  •  

Enrichment & Training

Enrichment

  • Behavioral Relevant Information
    • Raptors seize and rip apart their prey. Offering whole prey items, shreddable enrichment items, items they can grab and manipulate with their talons or shred with their beaks are all good forms of enrichment. 
  • Environmental Enrichment 
    • Changing perches within their habitat.
    • Addition of browse. 
  • Behavioral Enrichment 
    • The most successful enrichment devices appear to be items that can be footed and shredded, such as paper products, cardboard boxes, lettuce, melons, squash or other produce. These items can be provided alone or stuffed with prey or diet, although raptors should be monitored for ingestion of foreign objects if food is delivered with a novel item. Other successful items include tennis balls, holl-ee rollers, and canvas dog toys, which present opportunities for seizing, grabbing, mock “killing,” and mantling.
    • San Francisco Zoo: Their kestrel is offered enrichment daily; items include cardboard boxes/tubes, paper bags, various substrates (i.e. Carefresh bedding, aspen shavings, newspaper), balls, ice treats, Kongs, puzzle feeders, corn husks, plastic toys.
  • Schedule 
    • Daily enrichment is recommended. 
  • Other Enrichment Resources 
    • AZA’s Raptor TAG has a comprehensive list of raptor-appropriate enrichment as well as other suggestions on raptor enrichment programs on their website.

Training

  • Behaviors Trained
    • Note any behaviors this species is trained for, both for husbandry, crating/transport, or for programming. 
    • Can the public participate in any trained behaviors?
    • San Francisco Zoo: Their kestrel is trained in the following behaviors:
      • Voluntary step-up/step-down
      • Voluntary weight 
      • A → B flights between trainers, perches, and platforms
      • Hover
      • Voluntary application/removal of equipment (anklets stay on, but jesses are put on/removed; anklets are made from kangaroo leather with size 00 grommet; jesses are small braided from Northwoods Falconry)
      • Voluntary nail trim (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

  • Reinforcers used & schedule of reinforcement 
    • Using food and/or weight management as part of a good behavioral management program facilitates training by creating a learning environment in which birds want to participate. Training strategies that involve reducing food offered to the point of compromising the health of the bird are considered unacceptable. Food management and weight management practices that are safe for the bird and trainers, provide for the health and welfare of the bird, and facilitate training are recommended. 
  • Food and or weight management should be done with an understanding of the process and considerations. The decision to use weight management should not be taken lightly nor undertaken at all by staff who do not have a comprehensive understanding of managing weight and diet. 

Other

Colony or Breeding Management

  • Note if species is housed or managed socially or for breeding purposes.

Individual Identification

  • Dimorphism or practiced ways to individually mark species (such as those in colonies, like giant millipedes).

Programmatic Information

Messaging Themes

  •  This species is in decline across North America, though a pinpoint cause has yet to be determined.

Threats and Conservation Status

  • American Kestrels are not listed as endangered, due to their widespread range from North to South America, but their numbers are declining, and in some regions have dropped more than 88% since the 1960s, such as the Mid-Atlantic. While no cause has been pinpointed, this may be due to the use of pesticides, loss of hunting and nesting habitat, climate change, exposure to new zoonotic diseases (such as Avian Influenza and West Nile) and human encroachment. Though often cited, some have thought that increased predation from Cooper’s Hawks may have contributed to their decline, but this has since been refuted.
  • Prejudices against birds of prey still persist among many who wrongly believe that they harm wildlife or present major threats to domestic animals. Biological studies have documented their ecological importance as major controls on rodent populations. Some birds of prey feed on snakes, insects or other potential pests. No species of raptor poses a significant threat to domestic animals.
  • Instruct guests to never litter, especially when they are in a car. Throwing trash out along the roads not only makes the roads less attractive, but can also attract animals to the sides of the road. Some of these animals might look appetizing to an owl, hawk, or other predator which are then more likely to be hit by passing vehicles.
  • For more information, check out the Peregrine Fund’s American Kestrel Partnership and the Brandywine Zoo’s Delaware Kestrel Partnership.

Interesting Natural History Information

Did you know…

  • Kestrels are able to hover in the air while using their keen eyesight to search the ground below for prey.
  • Kestrels can see in the ultraviolet spectrum which allows them to locate fresh urine trails from rodents on the move
  • Like other birds of prey, falcons ingest all of the prey animal, and later regurgitate the less digestible parts into a small pellet. This is called “casting a pellet.”
  • Falcons can be distinguished from hawks by their long, tapered wings.

Handling & Presentation Tips

  •  

Use Guidelines

  • This species may be presented on glove, on perch, or in free-flight demonstrations. For tethered presentation, whether that is to the glove or to a perch, attention should be paid to avoid bating. Bating is not something that should be accepted from hawks, if there are instances of such, it is an indication of discomfort, with the handler or the situation, and that discomfort should be addressed, not ignored.
  • San Francisco Zoo: Their kestrel is presented in the following ways:
    • On hand with equipment
    • Free-flighted without equipment in enclosed spaces (i.e. classrooms, aviary)
    • In small bird aviary (transported to aviary in kennel)
    • On creance in open spaces (i.e. Wildlife Theatre) (see photo below)

Photo courtesy of Kaela Schnitzler, San Francisco Zoo

Pubic Contact and Interaction Guidelines

  • Public contact with this species is not advisable. 
  • Touching is not advisable.

Transportation Tips

  • Transport box suggestions Raptor Rig and Varikennel.
  • A couple things to keep in mind, crates should not be carried by the handle, but rather using two hands on either side of the crate and supporting it adequately. Swinging transport crates around and or moving them on a bumpy cart may create negative association for the bird, due to an uncomfortable ride and decrease the likelihood that the bird will go in the box on future occasions. If the perch is too low for the bird, their tail feathers may get painted with fecal matter which does not look good on presentation. 
  • San Francisco Zoo: Their kestrel is transported in a small Petmate Vari Kennel with installed perch and Astroturf lining

Crating Techniques

  • This species can be trained to voluntarily enter a crate either from the glove or directly from their enclosure. Continuous reinforcement of voluntary crate behaviors as well as dedication to their comfort and safety while in the crate is important to maintaining solid and reliable crate behavior.

Temperature Guidelines

  •  What temperature ranges can this animal be used outdoors? Any restrictions for travel that are temperature specific? How long can they be used at each temperature?

Acquisition Information

  • American kestrels are frequently available through rehabilitation organizations


Resources

Contributors and Citations

  • The Philadelphia Zoo
  • The Brandywine Zoo
  • San Francisco Zoo

Comments from the Rating System

  • Philadelphia Zoo: Tends to be flightier

Top Photo Credit: Kaela Schnitzler, San Francisco Zoo

Comments from the Rating System

  • Philadelphia Zoo: Tends to be flightier

Top Photo Credit: Kaela Schnitzler, San Francisco Zoo