Platalea ajaja

Platalea ajaja , Photo: Michael Lahanas

The roseate spoonbill (Platalea ajaja) is a gregarious wading bird of the ibis and spoonbill family, Threskiornithidae. It is a resident breeder in both South and North America. The roseate spoonbill's pink color is diet-derived, consisting of the carotenoid pigment canthaxanthin, like the American flamingo.
Taxonomy

The roseate spoonbill was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the current binomial name Platalea ajaja.[2] Linnaeus largely based his account on the "Aiaia" that been described and illustrated over a century earlier by the German naturalist Georg Marcgrave in his book Historia Naturalis Brasiliae.[3] Linnaeus specified the type locality as South America but this is now restricted to Brazil.[4][5] The genus name Platalea is Latin and means "broad", referring to the distinctive shape of the bill; the specific epithet ajaja is from the name for the species in the Tupi language as reported by Marcgrave.[6] The species is treated as monotypic: no subspecies are recognised.[7]

The roseate spoonbill is sometimes placed in its own genus – Ajaia. A 2010 study of mitochondrial DNA of the spoonbills by Chesser and colleagues found that the roseate and yellow-billed spoonbills were each other's closest relatives, and the two were descended from an early offshoot from the ancestors of the other four spoonbill species. They felt the genetic evidence meant it was equally valid to consider all six to be classified within the genus Platalea or alternatively the two placed in the monotypic genera Platibis and Ajaia, respectively. However, as the six species were so similar morphologically, keeping them within the one genus made more sense.[8]
Description

The roseate spoonbill is 71–86 cm (28–34 in) long, with a 120–133 cm (47–52 in) wingspan and a body mass of 1.2–1.8 kg (2.6–4.0 lb).[9] The tarsus measures 9.7–12.4 cm (3.8–4.9 in), the culmen measures 14.5–18 cm (5.7–7.1 in) and the wing measures 32.3–37.5 cm (12.7–14.8 in) and thus the legs, bill, neck and spatulate bill all appear elongated.[10] Adults have a bare greenish head ("golden buff" when breeding[11]) and a white neck, back and breast (with a tuft of pink feathers in the center when breeding), and are otherwise a deep pink. The bill is grey. There is no significant sexual dimorphism.

Like the American flamingo, their pink color is diet-derived, consisting of the carotenoid pigment canthaxanthin. Another carotenoid, astaxanthin, can also be found deposited in flight and body feathers.[12] The colors can range from pale pink to bright magenta, depending on age, whether breeding or not, and location. Unlike herons, spoonbills fly with their necks outstretched. They alternate groups of stiff, shallow wingbeats with glides.[13]
Distribution

In the United States, the species is locally common in Texas, Florida, and southwest Louisiana.[14] Generally, the species occurs in South America mostly east of the Andes, and in coastal regions of the Caribbean, Central America, Mexico, and the Gulf Coast of the United States,[15][16] and from central Florida's Atlantic coast[17] at Merritt Island National Wildlife Refuge, adjoined with NASA Kennedy Space Center at least as far north as South Carolina's Myrtle Beach.[18]

Plume hunting in the eighteenth and nineteenth centuries almost drove the roseate spoonbill to extinction.[19][14] However, following decades of conservation efforts, and the effects of climate change, the range of the roseate spoonbill has expanded considerably in the 21st century.[20][19] For instance, the species was recorded breeding in the state of Georgia for the first time in 2011. Moreover, its presence in South Carolina has expanded significantly since the 1970s,[19] as well as a single sighting of the bird in both Michigan and Wisconsin. The last known recorded log of the bird in the state of Wisconsin was of a deceased specimen in 1845 in Rock County. It made an historic reappearance 178 years later when a specimen was sighted by a crew that was doing birding surveys on the restricted-access Cat Island Causeway on July 27, 2023.

In the summer of 2021, sightings of the bird were reported well outside its typical range, including in Washington, D.C., upstate New York, and even New Hampshire.[21] A large flock was spotted in Huntley Meadows Park in Fairfax County, Virginia, drawing a large crowd of spectators.[22]

In Florida Bay, roseate spoonbills are an ecological and scientific indicator species. The number of nests varies with both the amount of fresh water and the depth of seawater there, as wetlands turn into open ocean. The birds are choosing to nest further north and inland in Florida, with sharp changes in nest locations noted in the years 2006–2020.[23]
Behavior

Little is known about the roseate spoonbill's behavior outside of their foraging habits.[24] This species feeds in shallow fresh or coastal waters by swinging its bill from side to side as it steadily walks through the water, often in groups. Moreover, the spoon-shaped bill allows it to sift easily through mud.[24]

The bird feeds on crustaceans, bits of plant material, aquatic insects, mollusks, frogs, newts and very small fish (such as minnows) ignored by larger waders.[24][25][26] In Brazil, researchers found roseate spoonbill diets to consist of fish, insects, crustaceans, mollusks, and seeds, all foraged from limnetic/freshwater habitats. This habitat specialization, combined with the relative plasticity of great egret foraging behavior, allows the two species to minimize competition during the breeding season.[27] Roseate spoonbills must compete for food with other freshwater birds, such as snowy egrets, great egrets, tricolored herons and American white pelicans.[citation needed] Roseate spoonbills are often trailed by egrets when foraging in a commensal "beater-follower" relationship, as the spoonbill's disturbance of the sediment makes prey more available to the egret (follower).[28]

Breeding

The roseate spoonbill nests in shrubs or trees, often mangroves, laying two to five eggs, which are whitish with brown markings.[13] Immature birds have white, feathered heads, and the pink of the plumage is paler. The bill is yellowish or pinkish. Nestlings are sometimes killed by turkey vultures, bald eagles, raccoons and invasive fire ants.[16]

Conservation and threats

Plume hunting in the eighteenth and nineteenth centuries almost drove the roseate spoonbill to extinction. However, it is currently considered not threatened. Information about predation on adults is lacking. In 2022, an 18-year-old banded bird was discovered, making it the oldest known wild individual.[29]
References

BirdLife International (2016). "Platalea ajaja". IUCN Red List of Threatened Species. 2016: e.T22697574A93621961. doi:10.2305/IUCN.UK.2016-3.RLTS.T22697574A93621961.en. Retrieved 19 November 2021.
Linnaeus, Carl (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin). Vol. 1 (10th ed.). Holmiae (Stockholm): Laurentii Salvii. p. 140.
Marcgrave, Georg (1648). Historia Naturalis Brasiliae: Liber Quintus: Qui agit de Avibus (in Latin). Lugdun and Batavorum (London and Leiden): Franciscum Hackium and Elzevirium. p. 204.
Berlepsch, Hans von (1908). "On the birds of Cayenne". Novitates Zoologicae. 15: 103–324 [301].
Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-List of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 268.
Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 157, 37. ISBN 978-1-4081-2501-4.
Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (December 2023). "Ibis, spoonbills, herons, Hamerkop, Shoebill, pelicans". IOC World Bird List Version 14.1. International Ornithologists' Union. Retrieved 23 July 2024.
Chesser, R.Terry; Yeung, Carol K.L.; Yao, Cheng-Te; Tians, Xiu-Hua; Li Shou-Hsien (2010). "Molecular phylogeny of the spoonbills (Aves: Threskiornithidae) based on mitochondrial DNA". Zootaxa. 2603 (2603): 53–60. doi:10.11646/zootaxa.2603.1.2. ISSN 1175-5326.
"Roseate Spoonbill Life History, All About Birds, Cornell Lab of Ornithology". www.allaboutbirds.org.
Hancock, Kushlan & Kahl (1992). Storks, Ibises, and Spoonbills of the World. Academic Press. ISBN 978-0-12-322730-0.
Howell, SNG; Webb, S (1995). A Guide to the Birds of Mexico and Northern Central America. Oxford University Press. pp. 147–8. ISBN 978-0-19-854012-0.
Brush, A. H. 1990. Metabolism of cartenoid pigments in birds. The FASEB Journal. 4:2969-2977.
Fox, D. L. 1962. Carotenoids of the Roseate Spoonbill. Comparative Biochemistry and Physiology 6:305-310.
(Mentioned in the Cornell Lab of Ornithology page).
Howell, SNG; Webb, S (1995). A Guide to the Birds of Mexico and Northern Central America. Oxford University Press. pp. 147–8. ISBN 978-0-19-854012-0.
"Roseate Spoonbill". Audubon. 2014-11-13. Retrieved 2022-12-31.
"Roseate Spoonbill". Waterbird Conservation. National Audubon Society. Archived from the original on 2008-10-24. Retrieved 2009-07-23.
Dumas, Jeannette V. 2000. Roseate Spoonbill (Platalea ajaja), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology. Retrieved 2009-11-12. (subscription required)
Graham Jr., Frank (July–August 2001). "Birds: A Wing and a Prayer". Audubon Magazine: 87–91.
Quinn, Joe. "Huntington Beach State Park in Murrells Inlet, South Carolina: White Heron, Roseate Spoonbill, American Alligator". Smithsonian Magazine.
Schools, Ben (2020-09-03). "The Roseate Spoonbill: A welcome presence, set to stay". Charleston Mercury. Retrieved 2022-12-31.
Miles, Suzannah (2020-10-22). "Follow the colorful life of the roseate spoonbill | Charleston Magazine". CHARLESTON SC |. Retrieved 2022-12-31.
"Tropical Pink Bird Spotted In D.C. For The First Time (It's Not A Flamingo)". DCist. Archived from the original on August 4, 2021. Retrieved 2021-08-04.
"Rarely-seen Spoonbills Draw Fans to Huntley Meadows Park".
Waters, Hannah (Winter 2022). "Flight of the Spoonbills". Audubon. pp. 18–27. Retrieved January 2, 2023. "Over the past 20 years the nesting range of Florida's Roseate Spoonbills has shifted north … Rising seas have seeped into the birds' historical foraging grounds in Florida Bay, driving them into shallower areas of Everglades National Park and beyond."
Dumas, Jeannette V. (2020). "Roseate Spoonbill (Platalea ajaja), version 1.0". Birds of the World. doi:10.2173/bow.rosspo1.01.
"The Online Guide to the Animals of Trinidad and Tobago - Ajaia ajaja (Roseate Spoonbill)" (PDF). University of the West Indies St. Augustine.
"Ajaia ajaja (Roseate spoonbill)". Animal Diversity Web.
Britto, Vanessa O.; Bugoni, Leandro (2015). "The contrasting feeding ecology of great egrets and roseate spoonbills in limnetic and estuarine colonies". Hydrobiologia. 744: 187–210. doi:10.1007/s10750-014-2076-1. S2CID 254541980.
Russell, James K. (1978). "Effects of Interspecific Dominance among Egrets Commensally Following Roseate Spoonbills". The Auk. 95 (3): 608–610. doi:10.1093/auk/95.3.608. JSTOR 4085177.
"Oldest Known Roseate Spoonbill Identified Thanks to Lucky Photograph Researchers: Oldest Wild Spoonbill Found - National Audubon Society". Audubon.org. 2022-04-18. Retrieved 2022-04-19.