Falco femoralisAplomado falcon

Geographic Range

Aplomado falcons (Falco femoralis) inhabit the neotropical and Nearctic biogeographic regions. They are residents throughout South America, Mexico, and the southern United States. Their range includes sites as far north as Arizona and New Mexico, and as far south as the South American country of Argentina. In South America, they inhabit Brazil, Bolivia, Paraguay, Uruguay, Colombia, Ecuador, Peru, Venzuela, Guyana, and Chile.

The nonbreeding populations of aplomado falcons include southern Texas in the United States, and central Mexico. Aplomado falcons are considered a partial migratory species, meaning most individuals are non-migratory. However, some individuals move for hunting during their non-breeding season, travelling northwards from November to February.

Captive releases in the United States have taken place, with over 1800 birds released from 1985 to 2012. These birds were reintroduced into their historical portions of their range, including southern and western Texas and New Mexico. (; Hector, 1986; Jenny, et al., 2004; Johnson, et al., 2021; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004; Mathys, 2011)

Habitat

Aplomado falcons are found in the United States in desert grasslands and coastal prairies. They also inhabit oak (Quercus) forest tracts scattered amidst these grasslands. Grasslands and forests along streams and other waterways are primary nesting and hunting sites. In Mexico and further south, they use coastal prairies and marshes, rainforest land that was recently cleared, and farmlands. These habitats are associated with a variety of palms (Sabal). Hector (1981) reported finding them commonly in savannah-like habitats - those dominated by scattered palm, oak, acacia (Acacia farnesiana), or calabash trees (Crescentia cujete). Coastal populations in South America will use open areas like beaches and tidal flats to forage. They can use anthropogenic sites like shrimp farms and rice (Oryza sativa) paddy fields.

Nests are found at frond bases of these palms and in large upper branches. Stick platforms on power-line poles as well as ground platforms have been occupied by released falcons in southern Texas.

Platform heights range from 2.3m to 11.3m above ground. Most nests are constructed by other raptors and are taken over by a mated aplomado falcon pair. While the females tend to the stick nest platform, the area surrounding it is the responsibility of the males.

Breeding and non-breeding habitats do not differ because most birds don’t migrate. The range of elevations across the geographic range is sea level to 4000 m. (Brown and Collopy, 2008; Hector, 1981; Hector, 1986; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004; Macías-Duarte, et al., 2021; Mathys, 2011; Montoya, et al., 1997; Silveira, et al., 1997)

  • Range elevation
    0 to 4,000 m
    0.00 to ft

Physical Description

Aplomado falcons weigh from 208-500g and total length ranges from 38-43cm. Females are consistently larger than males, as males are reportedly two-thirds the size of females. Males' reported mass ranges from 208-334g, while females ranged from 310-500g.

Adult male aplomado falcons possess a black or grey cap with similar dark stripes extending horizontally and vertically from their eyes. Their dorsal side is grey-blue and it continues to their upper tail. The remainder of their head and upper chest, plus their wingtips, are white. The lower breast and area around the cloaca are buff. These falcons' tails have alternating black-and-white bands visible in flight. Average measurements for males include wing-chords of 237mm, tail lengths of 153mm, and bill lengths of 15.5mm.

Female aplomado falcons are similar in appearance to males but have a longer average wing-chord of 263mm. They possess relatively darker or a cinnamon buff breast markings that also have wide dark streaks. Females' tails average 173mm and bill lengths are 18mm.

Hatchlings weigh 17.5g at possess white natal down. After 1-2 weeks post-hatching, young develop a grayish-dusky second natal down. Thin layers of dark upperpart feathers become distinct as juveniles, while breast and belly feathers lighten and lose dark markings as they age.

Similar birds species include prairie falcons (Falco mexicanus), who look similar in facial streaks. However, the amount of white on aplomado falcons' breasts and heads is greater than the other falcons. Prairie falcons appear browner in overall plumage. Further the long black streaks beginning on aplomado falcons' eyes are shorter on other falcons. Finally, the tail of aplomado falcons is thinner than similar species.

Basal metabolic rate has been estimated, based on bird size. It has been estimated as 905 kJ/day for a pair of birds. It is remarkably higher when parents are foraging to feed young; indeed, this metabolic demand can triple or quadruple when a pair is feeding 2 or 3 larger chicks. (Keddy-Hector, et al., 2020)

  • Sexual Dimorphism
  • sexes alike
  • female larger
  • Range mass
    208 to 500 g
    7.33 to 17.62 oz
  • Range length
    38 to 43 cm
    14.96 to 16.93 in

Reproduction

Aplomado falcons are presumed monogamous. Pair-bonds are expected to last multiple years, although higher rates of male mortality means that females may choose new (and younger) males in subsequent years. Age at first breeding is suspected to be two years old or greater.

During courtship, potential pairs jump from perch to perch and complete soaring behaviors for 15 to 20 min over a large area before diving to perch together. Both males and females will chase one another in flight as a part of courtship. They may also share prey items with one another in mid-air. Lone soaring males will fly above perched females before descending in a full-powered dive. Mating occurs, and the pair selects a nesting platform. Potential nest platforms are flown above or landed on by males before using a “chip” (Keddy-Hector et al., 2020) call to have the female join them. (Keddy-Hector, et al., 2020)

Aplomado falcons can pair-bond and reproduce by the end of their first year, although most do not do so until they are age 2 or older. In eastern Mexico, nesting occurs most often from mid-March to mid-April but the nesting period can extend from mid-February to late May. In southern tropical populations, clutch dates range from March to August to allow for re-nesting if reproduction is unsuccessful.

Macīas-Duarte et al. (2004) reported that timing of nesting was driven by rainfall from the previous summer, as it caused a cascade of events - more rain meant more seeds; more seeds meant more prey in the spring for the falcons. With greater prey densities, breeding and nesting began earlier in the season.

Eggs are whitish or buffy in color with brownish or rust-colored spots. In Texas and Arizona, twenty eggs from clutches measured 44.82mm in mean length. The normal clutch size contains two or, more often, three eggs; four eggs are rare. Based on observations in eastern Mexico, incubation is 31 to 32 days. At hatching, offspring are covered in white down, weighing 17.5g. Time until fledging is approximately 2 weeks. Four to five weeks after hatching, the young will begin to permanently leave the nest and become independent. (Hector, 1986; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004)

  • Breeding interval
    Aplomado falcons breed once yearly, but will renest if the first clutch fails
  • Breeding season
    March-August
  • Range eggs per season
    2 to 4
  • Range time to hatching
    31 to 32 days
  • Average fledging age
    2 weeks
  • Average time to independence
    4 weeks
  • Range age at sexual or reproductive maturity (female)
    1 (low) years
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Range age at sexual or reproductive maturity (male)
    1 (low) years
  • Average age at sexual or reproductive maturity (male)
    2 years

Keddy-Hector et al. (2020) studied two nest-sites in eastern Mexico and observed that seventy four percent of incubation time is performed by females, leaving the males to twenty six percent. A “chip” (Keddy-Hector et al. 2020) call is used by both falcons to indicate a switch in incubation responsibility. Females will leave the eggs untended during incubation to help assist males in chasing off potential predators.

In the first week after hatching, only the females brood their nestlings, while males hunt and bring food to the females. Females feed the young before feeding themselves until fledging, when the males will begin to assist feeding. Hector (1981) reported that nestlings were mostly fed birds (63% of items) and insects (34.2%).

Fledglings will rarely return to the nesting platform after their first flight. Sibling groups have been observed to travel and hunt together. (Hector, 1981; Keddy-Hector, et al., 2020)

  • Parental Investment
  • altricial
  • male parental care
  • female parental care
  • pre-hatching/birth
    • provisioning
      • male
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

Aplomado falcons have a reported maximum longevity of up to 12 years in the wild. Most aging data is from captive-raised and wild-released birds; these birds lived 6 to 8.75 years in the wild. As adults, survivorship of adults can approach 90%. However, nestling and fledgling survival is much lower; in nests of 3, typically 1 to 2 make it to fledging. wild fledglings have a 37% survival rate, while captive-reared fledglings have just a 17% survival rate.

In captivity, three birds exceeded 20 years of age, with one living at least 24 years.

Predatory animals like owls and hawks account for most young deaths, as well as lightning strikes, wire collisions, and starvation. (Keddy-Hector, et al., 2020)

  • Range lifespan
    Status: wild
    12 (high) years
  • Range lifespan
    Status: captivity
    24 (low) years
  • Typical lifespan
    Status: wild
    6 to 8.75 years

Behavior

Aplomado falcons usually remain in pairs for their lifetime, although they may choose another mate if one dies. Siblings will also remain and move together following fledging until mating. Two-week-old nestlings begin to play by grabbing objects, including sticks and bones. Fledglings older than two weeks will grab branches and flowering plants. Adults play by chasing large prey without capturing them. Play occurs in flight as well as on foot. After the young are about 1 month old, they will venture out on their own, yet maintain overlapping home ranges with members of their clutch. True dispersal occurred after 2-3 months, as Marcias-Duarte et al. (2021) found. They reported that a male falcon's first attempt at pair-bonding and breeding was just 15 km from his natal nest.

Keddy-Hector et al. (2020) summarizes studies in Mexico. Here, aplomado falcons were territorial of their nests, attacking all raptors and corvids near nesting sites containing fledglings and eggs. Male aplomado falcons initiated 64% of these attacks. Females will help in typical attacks, leaving the eggs or young unattended. Males target most intruders in flight, whereas females will attack intruders, including human researchers, more aggressively, with diving strikes.

Aplomado falcons are partially migratory, but most individuals do not migrate seasonally. Those that do migrate, do so in search of food resources, and only from November to February.

These birds are diurnal and hunt using visual and tactile techniques. Pairs will hunt together, and their success is more than double that of individual hunters. They tend to fly with speed and sneak up on birds and insect prey. They also practice kleptoparasitism, which is stealing prey from other falcons. The typically stolen prey reported by Brown et al. (2003) was mammals.

There are brief periods during the afternoon where diurnal sleep will occur. Roosting occurs at night near the innermost part of upper branches. (Brown, et al., 2003; Hector, 1985; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004; Macías-Duarte, et al., 2021; Tutuli Montijo Tautimes, 2021)

Home Range

Aplomado falcons occupy nests within 0.25 m of vegetation. Nesting sites in eastern Mexico were found 1 km or less apart from one another. These falcons had home ranges of 2.6-9.0 km^2. In southern Texas, falcons with nests on Matagorda Island had average home ranges of 3.9 km^2, while in Chihuahua, Mexico, 10 pairs with nests recorded an average home range size of 40km^2. Falcon pairs will defend their own nest-site, especially with eggs or fledglings in them. However, territory size was not quantified, and may just be the immediate area around a nest.

Juvenile aplomado falcons in Chihuahua, Mexico were equipped with transmitters at about 1 month old. Fully independent, they did not emigrate far from their natal range and experienced a high degree of overlap among siblings. Home range was reportedly higher than that of adults, averaging 170 km^2 (range 86 km^2 to 288 km^2). Similarly, a 2-y-old male falcon had a reported home range of 200 km^2 (Macías-Duarte et al., 2021). (Keddy-Hector, et al., 2020; Macías-Duarte, et al., 2021; Tutuli Montijo Tautimes, 2021)

Communication and Perception

Aplomado falcons have 4 recognizable calls, a “kek” or “ki” (Hector, 2020), a chip, a wail, and a chitter, harmonics included. Females have a lower frequency call than males, whereas fledglings have high-pitched calls, usually when hungry or at the sight food. The call, chip, is used in the context of food or feeding, and is used by both breeding and non-breeding falcons. Kek is most likely to be used by unmated adults who can recognize their own species. Because mated pairs remain and hunt together, wail may be used, but is usually used during their breeding season.

These falcons presumably use tactile senses to hunt, to consume shared prey, to mate, and to feed young. Like all raptors, they possess color vision and depend on it for successful foraging. They hunt cooperatively as pairs, and are observed looking for prey items high up in trees, on posts, or in flight. They can detect prey when hovering too. (Hector, 1986; Hunt, et al., 2013; Jenny, et al., 2004; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004; Mathys, 2011; Montoya, et al., 1997; Ricardo and Ema Soraya, 2005; Silveira, et al., 1997)

Food Habits

In the U.S. and Mexico, aplomado falcons’ diets consist mainly of birds (over 100 species recorded), such as horned larks (Eremophila alpestris), Brewer’s sparrows (Spizella breweri), lark buntings (Calamospiza melanocorys), and lark sparrows (Chondestes grammacus). Hector (1981) investigated pellets below nests in Mexico, and found that the most common avian species consumed were mourning (Zenaida macroura) and white-winged (Zenaida asiatica) doves, groove-billed anis (Crotophaga sulcirostris), great-tailed grackles (Quiscalus mexicanus), and yellow-billed cuckoos (Coccyzus americanus). Wasps, bees, and termites (order Hymenoptera), cicadas (order Homoptera), and mayflies (order Ephemeroptera) are insects that are also principal prey of this species.

In Mexico, Hector (1985) found that falcons had bird parts making 94% of items in prey remains and comprised 97% of biomass consumed. However, they fed on insects (each with substantially lower biomass than birds) that was dominated by beetles (order Coleoptera) and moths (order Lepidoptera).

Mammal prey included small rodents like kangaroo rats (Dipodomys), pocket mice (Perognathus) and deer mice (Peromyscus), as well as bats. Other mammals in South America include cavies (Galea musteloides) and European hares (Lepus europeus). During the spring and summer seasons, more birds and fewer rodents are found to be the prey.

They consume reptiles and amphibians uncommonly. Across their range, diet components have included coral snakes (Micrurus), Patagonia green racers (Philodryas patagoniensis), ocellated whiptail lizards (Teius oculatus) and those in the genus Liolaemus. There is one record of aplomado falcons catching an unidentified toad (Bufo).

These falcons have consumed fiddler crabs (Uca subcylindrica), as well.

Aplomado falcons often hunt as pairs. Hector (1986) reported that 66% of hunts were completed as pairs, and that success rate (44%) was more than double that of solo hunts (19%). Paired hunting, however, does not seem to affect the size of the prey selected. Kleptoparasitism (stealing food items from other falcons) occurred in populations in Texas and Mexico, and the typical stolen item was a large vertebrate. This stealing accounted for 14% of what was deemed a successful hunt for these falcons, and was nearly 3 times as successful as obtaining their own food by hunting. (Brown, et al., 2003; Hector, 1981; Hector, 1985; Hector, 1986; Hunt, et al., 2013; Keddy-Hector, et al., 2020; Macīas-Duarte, et al., 2004; Mathys, 2011; Montoya, et al., 1997; Ricardo and Ema Soraya, 2005; Silveira, et al., 1997)

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • amphibians
  • reptiles
  • insects
  • aquatic crustaceans

Predation

Aplomado falcon eggs and fledglings are hunted for food by great horned owls (Bubo virginianus), Harris’s hawks (Parabuteo unicintus), and prairie falcons (Falco mexicanus).

Keddy-Hector et al. (2002) summarized high depredation rates in captive-reared aplomado falcons following release. One sample in southern Texas found nine of 38 fledglings were preyed upon within two weeks post-release. In four of 30 nesting attempts, broken eggshells and missing nestlings were observed in eastern Mexico, suggesting predation had occurred.

There are no reports of adult aplomado falcons being preyed upon. Presumably, their size and speed make them harder for larger birds to capture. (Keddy-Hector, et al., 2020)

Ecosystem Roles

Aplomado falcons mostly eat birds and insects, but also bats, small rodents, and lizards. Young falcons are preyed upon by larger birds of prey, but no adult predators have been reported.

Aplomado falcons can be parasitized by botfly (Philornis) infestations. They can also be parasitized by a protozoan flagellate in the phylum Metamonada (Trichomonas). (Keddy-Hector, et al., 2020)

Commensal/Parasitic Species
  • bot fly (Philornis)
  • protozoan in phylum Metamonada (Trichomonas)

Economic Importance for Humans: Positive

Female aplomado falcons with an average flying weight of 356g have been listed for sale in the U.S. at an average price of $1,700. Females are larger than males and can reproduce, so they are sold at higher price. Falcon young have been listed at $2,000 for females and $1,800 for males. Prices can be dependent on availability and are only sold to licensed general or master class falconers. Some states allow for the flying of captive bred raptors by apprentices. (Ingram, 2022; MacAlpine, et al., 2022)

Economic Importance for Humans: Negative

Aplomado falcons have no reported negative impacts on humans. (Keddy-Hector, et al., 2020)

Conservation Status

Aplomado falcons are listed on the IUCN Red List as a species of “Least Concern”. On the list of Conservation of Tropical Raptors, this species is listed as “Not Threatened.” They are also protected by the Migratory Bird Treaty Act. This act is enforced by the U.S. Fish and Wildlife Service to regulate possession, taking (killing), transportation, sale, and export-import of protected birds. The US Endangered Species List has had the subspecies of the northern aplomado falcon (Falco femoralis septrententrionalis) listed since 1986.

In the state of Texas, they are also considered state endangered. Threats observed in southeastern Arizona, southern New Mexico, and western and southern Texas included severe overgrazing by domestic livestock due to the introduction of cattle in areas occupied by aplomado falcons in the late 1800s. Climate change has also been an affecting factor of the disappearance of this species. One of the biggest causes of population decline has been linked to pesticide contamination including DDT and DDE insecticides.

Birdlife International (2018) lists that aplomado falcons are internationally traded and used as pets, specifically for use in falconry. Appendix II of CITES bans the export of all live native birds. Further, a CITES permit is required for all captive breeding efforts, whether for future release into the wild or for falconry.

Aplomado falcons have been occasionally hunted in both the U.S. and Mexico due to the frequency of gamebirds, such as doves and quails, in their diet. Their presence in urban and suburban areas while hunting has led to additional deaths by humans.

Although numbers in the U.S. are rising (due to reintroduction efforts), the main reasons for decline are habitat loss and habitat conversions to farming or overgraded livestock pastures. Drought and subsequent loss of suitable prey also are factors. The Recovery Plan created by the U.S Fish and Wildlife Service to list goals of conservation for the species. Its primary objective was to create a self-sustaining population in the U.S. Hunt et al. (2013) concluded that successful recovery in the U.S. requires habitat protection of breeding habitats, which are savannah-like grasslands lacking shrub encroachment. Shrubby areas increase the numbers of predatory great horned owls (Bubo virginianus), which can decimate aplomado falcon populations. Additional studies on habitat requirements and availability, as well as population biology and behavior, will help managers better understand these falcons. (BirdLife International, 2018; "Code of Federal Regulations", 1973; ; Hector, 1981; Hector, 1986; Hunt, et al., 2013; Keddy-Hector, et al., 2020; Miller, 2020)

Contributors

Helena Willson (author), Radford University, Sierra Felty (editor), Radford University, Bianca Plowman (editor), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

References

National Archives. Code of Federal Regulations. Title 50. eCFR: National Archives. 1973. Accessed April 25, 2022 at https://www.ecfr.gov/current/title-50/part-10.

BirdLife International, 2018. "Falco femoralis" (On-line). The IUCN Red List of Threatened Species 2018: e.T22696450A131940332. Accessed May 03, 2022 at https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22696450A131940332.en.

Brown, J., M. Collopy. 2008. Nest-site characteristics affect daily nest-survival rates of northern aplomado falcons (Falco femoralis septentrionalis). The Auk, 125/1: 105-112.

Brown, J., A. Montoya, E. Gott, M. Curti. 2003. Piracy as an important foraging method of aplomado falcons in southern Texas and northern Mexico. The Wilson Bulletin, 115/4: 357-359.

Hector, D. 1985. The diet of the aplomado falcon (Falco femoralis) in eastern Mexico. The Condor, 87/3: 336–342.

Hector, D. 1981. Habitat, Diet, and Foraging Behavior of the Aplomado Falcon, Falco femoralis (Temminck) (Master's Thesis). Stillwater, OK: Oklahoma State University.

Hector, D. 1986. Cooperative hunting and its relationship to foraging success and prey size in an avian predator. Journal of Animal Ecology, 73/3: 247-257.

Hunt, W., J. Brown, T. Cade, J. Coffman, M. Curti, E. Gott, W. Heinrich, J. Jenny, P. Juergens, A. Macías-Duarte, A. Montoya, B. Mutch, C. Sandfort. 2013. Restoring aplomado falcons to the United States. Journal of Raptor Research, 47/4: 335-351.

Ingram, J. 2022. "Falcons of Steel: Aplomado Falcons" (On-line). Accessed April 25, 2022 at https://www.aplomadofalcons.com/who-we-are.html.

Jenny, J., W. Heinrich, A. Montoya, C. Sandfort, W. Hunt. 2004. Progress in restoring the aplomado falcon to southern Texas. Wildlife Society Bulletin, 32/1: 276-285.

Johnson, J., A. Stock, P. Juergens, B. Mutch, C. McClure. 2021. Temporal genetic diversity and effective population size of the reintroduced aplomado falcon (Falco femoralis) population in coastal south Texas. Journal of Raptor Research, 55/2: 169-180.

Keddy-Hector, D., P. Pyle, M. Patten. 2020. "Aplomado Falcon (Falco femoralis) version 1.0" (On-line). Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY. Accessed February 12, 2022 at https://doi.org/10.2173/bow.aplfal.01.

MacAlpine, A., M. Fauteaux, M. Maxcy. 2022. "Aplomado Falcon For Sale" (On-line). Raptors Etc. Accessed April 25, 2022 at https://www.raptorsforsale.com/sale/aplomado-falcon-for-sale.asp.

Macías-Duarte, A., A. Montoya, J. Rodriguez-Salazar, J. Alvarado-Castro, O. Gutiérrez-Ruacho. 2021. Natal dispersal of aplomado falcons in Chihuahua, Mexico. Journal of Raptor Research, 55/2: 267-275.

Macīas-Duarte, A., A. Montoya, W. Hunt, A. Lafón-Terrazas, R. Tafanelli. 2004. Reproduction, prey, and habitat of the aplomado falcon (Falco femoralis) in desert grasslands of Chihuahua, Mexico. The Auk, 121: 1081-1093.

Mathys, B. 2011. First record of aplomado falcon (Falco femoralis) for the West Indies. The Wilson Journal of Ornithology, 123/1: 179-180.

Miller, G. 2020. "The Aplomado Falcon" (On-line). Pennsylvania Falconry and Hawk Trust. Accessed April 25, 2022 at http://www.pfht.org/falconry/raptors/aplomado-falcon/.

Montoya, A., P. Zwank, M. Cardenas. 1997. Breeding biology of aplomado falcons in desert grasslands of Chihuahua, Mexico. Journal of Field Ornithology, 68/1: 135-143.

Mora, M., M. Lee, P. Jenny, T. Schultz, J. Sericano, N. Clum. 1997. Potential effects of environmental contaminants on recovery of the aplomado falcon in south Texas. The Journal of Wildlife Management, 61/4: 1288-1296.

Ricardo, F., C. Ema Soraya. 2005. Seasonal diet of the aplomado falcon (Falco femoralis) in an agricultural area of Araucania, southern Chile. Journal of Raptor Research, 39/1: 55-60.

Silveira, L., A. Jácomo, F. Rodrigues, P. Crawshaw Jr. 1997. Hunting association between the aplomado falcon (Falco femoralis) and the maned wolf (Chrysocyon brachyurus) in Emas National Park, central Brazil. The Condor, 99/1: 201-202.

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