Ara militarismilitary macaw

Geographic Range

Military macaws (Ara militaris) are split up into eight disjunct ranges – two in Mexico and six in South America. Military macaws are absent in Central America. The northernmost portion of their range extends as far as La Sierrita (Sonora), Mexico. This range follows the western coast of Mexico and continues south to Las Margaritas. Within this range, from Lazaro Cardenas to Las Margaritas they may be extinct. The extant regions are from Sahuaripa to the northern tip of Choix. The range in Mexico also includes an area on the eastern coast from Cuidad Victoria to Tantoyuca. Within this region, a small area near Cuidad Mante, Tamaulipas contains an extant population.

In South America, the first of the six disjunct ranges includes northern Colombia, south along the Colombia-Venezuela border, to Ocana. The second portion of the macaws’ range is further west into Colombia following a mountainous range from Bolivar to Trujillo, Valle del Cauca. The third disjunct region includes Colombia starting at Granada and continuing southeast to Napo. The fourth region is in Peru as far north as the Amazonas: it ranges through central Peru to the southern point of Huanuco. The fifth disjunct portion of the macaws’ range includes Parque Nacional del Manu and continues south into Caranavi, Bolivia. The last region is in Bolivia, from Cochabamba at the northern most point directly southward into Argentina until the town of Caimancito. There are no migration patterns for military macaws.

Military macaw subspecies have non-overlapping ranges. Individuals in the subspecies Ara militaris mexicanus are limited to western and northeastern Mexico. Members of Ara militaris militaris inhabit northern Venezuela, the Andes of Colombia, eastern Ecuador, Peru, and western Bolivia. Members of the subspecies Ara militaris bolivianus populate areas from central Bolivia to northern Argentina. (BirdLife International, 2016; Collar, et al., 2020; Rivera-Ortíz, et al., 2013)

Habitat

Military macaws inhabit tropical, terrestrial biomes that include tropical sub-deciduous and deciduous forest as well as rainforest. Their elevational range is from 0 to 3600 m, but they are most commonly found at elevations between 500 to 1500 m. They utilize tree cavities for the purpose of nesting. In South America they generally live in humid forests, highly wooded areas, and shaded coffee plantations. These birds move locally to and from forests and shaded regions.

Nesting locations include the side of cliffs or large communal roosting trees, depending on availability. Communal roosts are found in trees taller than 16 m, such as those in tropical, semi-deciduous forests. If they do nest in trees a requirement is a DBH (diameter breast height) of greater than 50 cm. When tree cavities are unavailable, military macaws nest instead in cavities on karst cliffs. (BirdLife International, 2016; Parra-Martínez, et al., 2014; Rivera-Ortíz, et al., 2013)

  • Range elevation
    0 to 3600 m
    0.00 to 11811.02 ft

Physical Description

Military macaws are blue and green, with a paler shade of green on their head compared to their body. There is a red patch on their foreheads and an exposed white area with dark lines around the eye. Their flight quills are blue and their tail feathers are red. The have a large black beak and yellow eyes.

They weigh around 900 g, are roughly 70 to 80 cm long, and have wingspans of 99 to 110 cm. They are monomorphic, which means that the male and female resemble each other. The average basal metabolic rate for parrots (not specific to military macaws) is 1.8 cm^3 oxygen/gram hour; the basal metabolic rate specific to military macaws has not been reported. They are born naked with no feathers and then will reach sexual maturity at around two to four years. (Bryan, 2020; Montgomery, et al., 2011)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    900 g
    31.72 oz
  • Range length
    70 to 80 cm
    27.56 to 31.50 in
  • Range wingspan
    90 to 110 cm
    35.43 to 43.31 in
  • Average basal metabolic rate
    1.8 cm3.O2/g/hr

Reproduction

Military macaws are monogamous, staying with one mate for life. They are seasonal breeders. They can breed year-round in captivity; they might breed year-round in the wild depending on existing bonds, cavity availability, and resource availability. These macaws are secondary cavity-nesters, meaning that they will use pre-formed nesting cavities on the sides of cliffs or in tall trees. Rivera-Ortiz (2016) summarized a number of publications and reported that the behaviors of grooming and regurgitation were observed between pairs as a way to strengthen their bonds. (Bryan, 2020; Jordan and Moore, 2015; Rivera-Ortíz, et al., 2016a)

Ara militaris breeding seasons vary in each disjunct location in which they are found. Breeding season in northwestern Mexico is from March to October. In western Mexico, breeding starts with the selection of nests from October to November and ends when the juveniles leave the nest between January and March. The breeding season in central Mexico is from May to September. Breeding seasons in these different regions vary due to resource availability and the phenology of sympatric tree species.

Military macaws generally breed every 1 to 2 years and average 2 to 3 eggs in a single clutch. In captivity, hatching time averages 26 days and hatchlings weigh 18 to 25 g. Their time to fledging averages 13 weeks and their time to independence (when they leave) the nest is between 3 to 5 months. Age of sexual maturity in military macaws is the same for both sexes: 2 to 4 years. (Bryan, 2020; Rivera-Ortíz, et al., 2008; Rivera-Ortíz, et al., 2016a)

  • Breeding interval
    Military macaws breed every 1 to 2 years.
  • Breeding season
    January-November, depending on location.
  • Range eggs per season
    2 to 3
  • Average eggs per season
    2
  • Average time to hatching
    26 days
  • Average fledging age
    13 weeks
  • Range time to independence
    3 to 5 months
  • Range age at sexual or reproductive maturity (female)
    2 to 4 years
  • Range age at sexual or reproductive maturity (male)
    2 to 4 years

Military macaws are altricial, meaning chicks are born fully dependent on both parents. In the pre-fertilization period, males protect and feed females. During the pre-hatching period provisioning and protecting of eggs is performed by both sexes. Males continues to protect and feed females while they are incubating eggs. In the pre-weaning, fledging, and pre-independence periods both sexes feed and protect young. Military macaws generally inherit territory from their parents. (Rivera-Ortíz, et al., 2016a)

  • Parental Investment
  • altricial
  • male parental care
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • male
      • female
  • pre-hatching/birth
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • inherits maternal/paternal territory

Lifespan/Longevity

The maximum life span of the military macaws in captivity is 54 years. There are many web-based sources that suggest a lifespan of around 50-60 years in the wild, but at this time, no reputable source exists to support this range. (Brouwer, et al., 2000; Young, et al., 2011)

  • Range lifespan
    Status: captivity
    54 (high) years

Behavior

Military macaws are gregarious, meaning they are social birds. Although populations of 50 macaws are common, they have been found in groups of up to 100. Despite living in colonies, they forage independently or fly in pairs. As pairs, these birds seek out suitable nesting areas. Juveniles remain with their parents until they are fully independent. Rivera-Ortiz (2016) summarized multiple publications and reported that the breeding season in western Mexico is from October to November and it ends with the departure of the juveniles from January to March.

These birds are not migratory, but they move seasonally based on the abundance of food and number of suitable breeding sites. They move daily among feeding, nesting, and roosting sites. Like most birds, flight is the main mode of locomotion for military macaws. However, they can climb up and around trees. Military macaws are diurnal, meaning the are active during the day.

Vocalization for macaws is unrelated to the selection of mates but is often used for defending nesting sites. For parrots, including military macaws, part of their vocal learning is mimicry. These macaws gain a large repertoire throughout their lives, as both sexes vocalize at all ages, and sexes learn vocalization in the same manner. (Bonilla-Ru, et al., 2007; Parra-Martínez, et al., 2014; Rivera-Ortíz, et al., 2008; Rivera-Ortíz, et al., 2016a)

  • Range territory size
    1 (high) m^2

Home Range

Home ranges for military macaws have not yet been reported. However, Bonnila-Ruz et al. (2007) reported that macaws travel a linear distance of around 20 km foraging throughout the day. Abundance and availability of food determine travel distances. Although territory sizes have not been reported, military macaws do protect their nesting sites. Given nest sizes, territory has been estimated to be less than one square meter. (Bonilla-Ru, et al., 2007; Collar, et al., 2020)

Communication and Perception

Military macaws have an extremely developed sense of vision, primarily used for finding food and detecting predators. These birds can sense Earth's magnetic fields, which helps them navigate their environment. They have excellent color vision, and so communicate with colorful courtship displays. Hearing is essential to their communication and perception of the world; it helps military macaws defend territory, navigate, and mate. Their sense of taste is important in selecting food. Military macaws can taste sweet, sour, bitter, salty flavors, and can detect lipid and sugar concentrations in their food. Their sense of smell helps them to select mates and detect food while foraging.

Another way military macaws communicate is through a grooming and regurgitating behavior between males and females. These behaviors strengthen bonds between monogamous pairs of macaws. However, this behavior is still seen during non-breeding periods. They have distinct vocalizations for a wide variety of activities. They use vocalizations as alarm calls, during territorial disputes, and while mating.

There is evidence of call differences between separate military macaw populations. Macaws within an area will have similar calls, while a geographically separated group might sound different. This species, like all macaws, perform distinct croaking vocalizations every morning, and again around sunset. (Bryan, 2020; Gill, 2007; Rivera-Ortíz, et al., 2016a)

Food Habits

Military macaws are specialized granivores, meaning they primarily eat seeds. Their range of seeds in their diet differs seasonally based on abundance and availability. Their diet can also differ depending whether not it is breeding season. Macaws have been reported eating arbol del diablo (Hura polyandra) and the breadnut, or Maya nut, (Brosimum alicastrum) in the highest frequencies. However, macaws’ seed proportions vary by location and availability.

Military macaws have been observed getting water from the leaves of air plants (Tillandsia grandi) and eating the stems of nosegay (Plumeria rubra) to consume the latex. Military macaws commonly forage in semi-deciduous forests, due to a greater amount of fruiting trees, when compared to deciduous forest. They are also known to eat fruit, bark, wood and leaves. (Contreras-González, et al., 2009; Rivera-Ortíz, et al., 2016b)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit

Predation

Parra-Martínez et al. (2014) reported collared forest falcons (Micrastur semitorquatus) are a nest-predator and a nest-site competitor of the military macaws.

Military macaws nest in cavities in trees or cliff sides, providing them cover and protection from predators. (Parra-Martínez, et al., 2014; Rivera-Ortíz, et al., 2013)

Ecosystem Roles

Military macaws are specialized granivores, which means they primarily eat seeds. This leads to seed dispersion of multiple plant species. Additionally, these macaws and their eggs are a prey item for collared forest falcons (Micrastur semitorquatus).

Bennett et al. (1991) found an unknown protozoan parasite from the genus Haemoproteus or Plasmodium in an individual military macaw. Some other parasites that affect military macaws are chewing lice from the suborders Amblycera and Ischnocera. Chewing lice species recorded on military macaws include Heteromenopon militaris, Psittacobrossus carrikeri, Psittacobrossus ambiguous, Epiara dimorpha and Paragoniocotes militaris.

There are also other types of parasites that are often found captive military macaws. Nematode parasites (Capillaria caudinflata) are found in the small intestine of military macaws. At the Columbus Zoo in Ohio, one male military macaw had an unidentified egg from a parasitic worm (helminth) and a coccidian (protozoan) parasitic egg in their fecal matter. At the Kamla Nehru Zoological Garden, Kankaria Zoo, Ahmedabad, India, there was an individual military macaw that had a gastrointestinal parasite, but the species of the parasite was not listed. (Bennett, et al., 1991; Faust and Pappas, 1977; Martínez, et al., 2015)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species
  • Protozoan Haemoproteus
  • Protozoan Plasmodium
  • Chewing louse Heteromenopon militaris
  • Chewing louse Psittacobrossus carrikeri
  • Chewing louse Psittacobrossus ambiguous
  • Chewing louse Epiara dimorpha
  • Chewing louse Paragoniocotes militaris
  • Nematode Capillaria caudinflata
  • Unknown parasitic worm eggs
  • Unknown protozoan/coccidian eggs

Economic Importance for Humans: Positive

A positive economic benefit for humans from the military macaw is very evident in ecotourism. Known bird-watching sites in South America attract both tourists and locals. A few sites are located in Tayrona National Park in Colombia, Loreto Road in Ecuador, Tingo Maria and Amazonia Lodge in Peru, and Guatapo National Park in Venezuela. Military macaws are common pets around the world. They are usually hatched in captivity and a general price range for them is around $1,000 to $3,000. Illegal bird smuggling is one way in which humans procure military macaws as pets. Birds that are illegally sold will be lower priced than captive-bred animals, may be collected outside of their breeding season, and will not be legally banded (a way to identify legal birds through the USDA). (Clubb, 1987; Wheatley, 1995)

Economic Importance for Humans: Negative

If a military macaw is purchased via illegal smuggling of wild-caught birds, it is possible for them to have diseases. If they are not legally banded by the USDA, they have not been through any type of quarantine process. New Castle disease is commonly found in military macaws. This disease can be deadly to other domestic animals (mostly birds) and will cause conjunctivitis in humans. (Clubb, 1987)

Conservation Status

On the IUCN Red List, military macaws are defined as “vulnerable”. These macaws have no special status on the US Migratory Bird Act. On the US Federal list, they are listed as Endangered. These birds are listed under Appendix I of CITES, meaning they are threatened with extinction and have certain protective measures around them. Trade of this species is only allowed in special circumstances, and import/export permits are required for any commercial trading of these birds.

The U.S. Fish and Wildlife Service announced in 2015 that military macaws were listed as endangered under the Endangered Species Act. Military macaws are considered endangered due to habitat and resource loss from logging and wood harvesting, which leads to habitat fragmentation and degradation. Their populations are also threatened by poachers from illegal pet trades.

The Endangered Species Act also has regulations put into place to help protect endangered foreign species. In the United States, it is illegal to import or export this species or any of its parts, to take or harm this species in any way, or to transport and deliver this species in the United States or foreign countries. Federal permits are required to legally import or export military macaws. The Endangered Species Act generally provides financial support, training, and sometimes even personnel for different programs ensuring the conservation of military macaws. While it is legal to own military macaws, breeding, purchasing, and distributing these birds is closely monitored. (BirdLife International, 2016; U.S Fish and Wildlife Service, 2019)

Contributors

Isabella Armstrong (author), Radford University, Lauren Burroughs (editor), Radford University, Logan Platt (editor), Radford University, Karen Powers (editor), Radford University, Galen Burrell (editor).

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

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.

causes disease in humans

an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).

causes or carries domestic animal disease

either directly causes, or indirectly transmits, a disease to a domestic animal

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

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

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

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).

magnetic

(as perception channel keyword). This animal has a special ability to detect the Earth's magnetic fields.

male parental care

parental care is carried out by males

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.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

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

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Aramburú, R. 2012. Insectos parásitos que afectan a loros de Argentina y métodos para su obtención. Revista de Ornittología Neotropical, 27/1: 103-116.

Bennett, G., A. Aguirre, R. Cook. 1991. Blood parasites of so birds from northeastern Mexico. The Journal of Parasitology, 77/1: 38-41.

BirdLife International, 2016. "Ara militaris" (On-line). The IUCN Red List of Threatened Species 2016: e.T22685548A93079238. Accessed February 03, 2020 at https://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22685548A93079238.en.

Bonilla-Ru, C., G. Reyes-Macedo, R. Garcia. 2007. Observations of the military macaw (Ara militaris) in northern Oaxaca, Mexico. The Wilson Journal of Ornithology, 119/4: 729-732.

Bonilla-Ruz, C., C. Cinta-Magallón, T. Monterrubio-Rico, L. Avilés-Ramos. 2018. Population assessment of military macaw (Ara militaris) inhabiting the southern coastal forests of Bahía de Banderas, Jalisco, Mexico. The Wilson Journal of Ornithology, 130/4: 859-869.

Bradbury, J., T. Balsby. 2016. The functions of vocal learning in parrots. Behavioral Ecology and Sociobiology, 70: 293–312.

Brouwer, K., M. Jones, C. King, H. Schifter. 2000. Longevity records for Psittaciformes in captivity. International Zoo Yearbook, 37: 299-316.

Bryan, P. 2020. Military Macaw: The Lovers Manual on How to Keep and Care for the Military Macaw. Kindle edition: Phil Bryan.

Clubb, S. 1987. Guidelines to recognizing potentially smuggled birds. AAV Today, 1/3: 130.

Collar, N., P. Boesman, C. Sharpe. 2020. "Military Macaw (Ara militaris), version 1.0." (On-line). Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Accessed April 19, 2020 at https://doi.org/10.2173/bow.milmac.01.

Contreras-González, A., F. Rivera-Ortíz, A. Valiente-Banuet, M. Arizmendi, C. Soberanes-González. 2009. Feeding ecology of military macaws (Ara militaris) in a semi-arid region of central México. The Wilson Journal of Ornithology, 121/2: 384-391.

Davies, C., R. Barnes, S. Butchart, M. Fernandez, N. Seddon. 1997. The conservation status of birds on the Cordillera de Colán, Peru. Bird Conservation International, 7/2: 181-195.

Eberhard, J., E. Iñigo-Elias, E. Enkerlin-Hoeflich, P. Cun. 2015. Phylogeography of the military macaw (Ara militaris) and the great green macaw (A. ambiguus) based on mtDNA sequence data. The Wilson Journal of Ornithology, 127/4: 661-669.

Faust, B., P. Pappas. 1977. A survey of coccidia and helminth parasites of birds at the Columbus (Ohio) Zoo. The Journal of Zoo Animal Medicine, 8/1: 18-23.

Gill, F. 2007. Ornithology Third Edition. New York, New York: W.H. Freeman and Company.

Jordan, R., M. Moore. 2015. A Guide to Macaws as Pet and Aviary Birds. Australia: ABK Publications. Accessed March 18, 2020 at https://issuu.com/birdandreptilebooks/docs/macaw_book_sneak_peak.

Martínez, F., V. Laffont, M. Rodríguez Camon. 2015. Capillaria caudinflata (Molin, 1858) en Ara rubrogenis y Ara militaris (Aves, Psittacidae). Revista Veterinaria Argentina, Unknown: Unknown. Accessed April 19, 2020 at http://www.veterinariargentina.com/res/resumenes247.pdf.

Montgomery, M., A. Hulbert, W. Buttemer. 2011. Metabolic rate and membrane fatty acid composition in birds: A comparison between long-living parrots and short-living fowl. Journal of Comparative Physiology B, 182: 127-137.

Parra-Martínez, S., K. Renton, A. Salinas-Melgoza, L. Muñoz-Lacy. 2014. Tree-cavity availability and selection by a large-bodied secondary cavity-nester: The military macaw. Journal of Ornithology, 156: 489-498.

Parsani, H., R. Momin, R. Sahu, B. Patel. 2003. Prevalence of gastro-intestinal parasites in captive birds at Kamla Nehru Zoological Garden, Kankaria Zoo, Ahmedabad, Gujarat. Zoo's Print Journal, 18/1: 987-992.

Rivera-Ortíz, F., A. Contreras-González, C. Soberanes-González, A. Valiente-Banuet, M. Arizmendi. 2008. Seasonal abundance and breeding chronology of the military macaw (Ara militaris) in a semi-arid region of central Mexico. Ornitologia Neotropical, 19/2: 255–263.

Rivera-Ortíz, F., K. Oyama, C. Ríos-Muñoz2, S. Solórzano, A. Navarro-Sigüenza, M. del Coro Arizmendi. 2013. Habitat characterization and modeling of the potential distribution of the military macaw (Ara militaris) in Mexico. Revista Mexicana de Biodiversidad, 84/4: 1200-1215.

Rivera-Ortíz, F., K. Oyama, C. Villar-Rodríguez, A. Contreras-González, M. Coro Arizmendi. 2016. The use of tree cavities and cliffs by the military macaw (Ara militaris) in Salazares Nayarit, Mexico. Revista Mexicana de Biodiversidad, 87/2: 540-544.

Rivera-Ortíz, F., S. Solórzano, M. Arizmendi, P. Dávila-Aranda, K. Oyama. 2016. Genetic diversity and structure of the military macaw (Ara militaris) in Mexico: Implications for conservation. Tropical Conservation Science, 10: 1-12. Accessed February 03, 2020 at https://journals.sagepub.com/doi/10.1177/1940082916684346.

Salinas-Melgoza, A., K. Renton. 2020. Geographic variation in vocalisations of the Military Macaw in western Mexico. Bioacoustics, None: None. Accessed February 17, 2020 at DOI: 10.1080/09524622.2020.1714479.

U.S Fish and Wildlife Service, 2019. "Endangered Species/Foreign Species" (On-line). Parrots. Accessed April 03, 2020 at https://www.fws.gov/endangered/what-we-do/parrots.html.

Wheatley, N. 1995. Where To Watch Birds in South America. Princeton, New Jersey: Princeton University Press.

Williams, I., W. Hoppitt, R. Grant. 2017. The effect of auditory enrichment, rearing method and social environment on the behavior of zoo-housed psittacines (Aves: Psittaciformes); implications for welfare. Applied Animal Behavior Science, 186: 85-92.

Young, A., E. Hobson, L. Lacey, T. Wright. 2011. Survival on the ark: Life-history trends in captive parrots. Animal Conservation, 15: 28-43.

de la Parra-Martínez, S., L. Muñoz-Lacy, A. Salinas-Melgoza, K. Renton. 2019. Optimal diet strategy of a large-bodied psittacine: Food resource abundance and nutritional content enable facultative dietary specialization by the military macaw. Avian Research, 10: 38. Accessed February 04, 2020 at https://doi.org/10.1186/s40657-019-0177-2.