Editing Frigatebird (section)

==Behaviour and ecology==
[[File:Prachtfregattvogel MM01.jpg|left|thumb|Magnificent frigatebirds drinking freshwater]]
Having the largest wing-area-to-body-weight ratio of any bird, frigatebirds are essentially aerial.<ref name=hbwFregatidae/> This allows them to soar continuously and only rarely flap their wings. One great frigatebird, being tracked by satellite in the Indian Ocean, stayed aloft for two months. They can fly higher than 4,000 meters in freezing conditions.<ref>{{ cite journal | last1=Weimerskirch | first1=H. | last2=Bishop | first2=C. | last3=Jeanniard-du-Dot | first3=T. | last4=Prudor | first4=A. | last5=Sachs | first5=G. | year=2016 | title=Frigate birds track atmospheric conditions over months-long transoceanic flights | journal=Science | volume=353 | issue=6294 | pages=74–78 | doi=10.1126/science.aaf4374 | pmid=27365448| bibcode=2016Sci...353...74W | s2cid=206648100 | url=https://research.bangor.ac.uk/portal/en/researchoutputs/frigate-birds-track-atmospheric-conditions-over-monthslong-transoceanic-flights(7871f444-35c6-4ce1-a788-df0bf321e7dd).html }}</ref> Like [[Swift (bird)|swift]]s they are able to spend the night on the wing, but they will also return to an island to roost on trees or cliffs.<ref name=weimerskirch03>{{cite journal | last1=Weimerskirch | first1=Henri | last2=Chastel | first2=Olivier | last3=Barbraud | first3=Christophe | last4=Tostain | first4=Olivier | year=2003 | title=Frigatebirds ride high on thermals | journal=Nature | volume=421 | pages=333–34 | url=http://www.cebc.cnrs.fr/publipdf/2003/WNat421.pdf | doi=10.1038/421333a | pmid=12540890 | issue=6921 | s2cid=4357404 | access-date=2014-12-23 | archive-date=2018-09-21 | archive-url=https://web.archive.org/web/20180921192153/http://www.cebc.cnrs.fr/publipdf/2003/WNat421.pdf | url-status=dead }}</ref><!-- cites previous 2 sentences --> Field observations in the [[Mozambique Channel]] found that great frigatebirds could remain on the wing for up to 12 days while foraging.<ref>{{cite journal | last1=Weimerskirch | first1=Henri | last2=Le Corre | first2=Matthieu  | last3=Jaquemet | first3=Sébastien  | last4=Potier | first4=Michel  | last5=Marsac | first5=Francis | year=2004 | title=Foraging strategy of a top predator in tropical waters: great frigatebirds in the Mozambique Channel | journal=Marine Ecology Progress Series | volume=275 | pages=297–308 | doi=10.3354/meps275297 | bibcode=2004MEPS..275..297W | url=https://www.int-res.com/articles/meps2004/275/m275p297.pdf | doi-access=free }}</ref> Highly adept, they use their forked tails for steering during flight and make strong deep wing-beats,<ref name=obrien/> though not suited to flying by sustained flapping. Frigatebirds bathe and clean themselves in flight by flying low and splashing at the water surface before preening and scratching afterwards.<ref name=hbwFregatidae/><!-- cites previous 2 sentences --> Conversely, frigatebirds do not swim and with their short legs cannot walk well or take off from the sea easily.<ref name=obrien/>

According to a study in the journal ''Nature Communications'', scientists attached an [[accelerometer]] and an [[electroencephalogram]] testing device on nine great frigatebirds to measure if they slept during flight. The study found the birds do sleep, but usually only using one hemisphere of the brain at a time and usually sleep while ascending at higher altitudes. The amount of time mid-air sleeping was less than an hour and always at night.<ref>{{cite news |last=Ferro |first=Shaunacy |url=http://mentalfloss.com/article/84220/can-birds-sleep-mid-flight-yes-new-study-confirms |title=Can Birds Sleep Mid-Flight? Yes, a New Study Confirms |work=[[Mental Floss]] |date=2016-08-04 |access-date=2019-09-19 }}</ref>

The average life span is unknown but in common with seabirds such as the [[wandering albatross]] and [[Leach's storm petrel]], frigatebirds are long-lived. In 2002, 35 ringed great frigatebirds were recovered on [[Tern Island (Hawaii)|Tern Island]] in the [[Hawaiian Islands]]. Of these ten were older than 37 years and one was at least 44 years of age.<ref name=juola>{{cite journal | last1=Juola | first1=Frans A. | last2=Haussmann | first2=Mark F. | last3=Dearborn | first3=Donald C. | last4=Vleck | first4=Carol M. | year=2006 | title=Telomere shortening in a long-lived marine bird: cross-sectional analysis and test of an aging tool | journal=The Auk | volume=123 | issue=3 | pages=775–83 | doi=10.1642/0004-8038(2006)123[775:TSIALM]2.0.CO;2 | s2cid=46907175 | url=http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1009&context=eeob_las_pubs | doi-access=free }}</ref>

Despite having dark plumage in a tropical climate, frigatebirds have found ways not to overheat—particularly as they are exposed to full sunlight when on the nest. They ruffle feathers to lift them away from the skin and improve air circulation, and can extend and upturn their wings to expose the hot undersurface to the air and lose heat by evaporation and convection. Frigatebirds also place their heads in the shade of their wings, and males frequently flutter their gular pouches.<ref name=hbwFregatidae/><!-- cites previous 3 sentences -->

Unlike most seabirds, frigatebirds are [[thermal soaring|thermal soarers]], using thermals to glide.<ref>{{cite journal | url=https://www.biorxiv.org/content/10.1101/2020.10.31.354605v1.full | doi=10.1093/pnasnexus/pgac023|biorxiv=10.1101/2020.10.31.354605 | title=Soaring styles of extinct giant birds and pterosaurs |journal= PNAS Nexus | year=2020 | last1=Goto | first1=Yusuke | last2=Yoda | first2=Ken | last3=Weimerskirch | first3=Henri | last4=Sato | first4=Katsufumi | pages=pgac023| s2cid=226263538|doi-access=free | pmid=36712794| pmc=9802081 }}</ref><ref>{{cite journal | url=https://www.jstor.org/stable/27838346 | jstor=27838346 | title=Thermal Soaring of Birds | last1=Cone | first1=Clarence D. | journal=American Scientist | year=1962 | volume=50 | issue=1 | pages=180–209 }}</ref> This is in contrast to birds like albatrosses, which are [[dynamic soaring|dynamic soarers]], using winds produced by the waves to stay aloft.

[[File:Soaring styles.png|thumb|Soaring styles in extinct and extant flyers. Frigatebirds are marked as thermal soarers.]]

===Breeding behaviour===
{{See also|Seabird breeding behavior}}
[[File:Fregata magnificens -Galapagos, Ecuador -male-8.jpg|thumb|right|Magnificent frigatebird male breeding display]]
Frigatebirds typically breed on remote oceanic islands, generally in colonies of up to 5000 birds. Within these colonies, they most often nest in groups of 10 to 30 (or rarely 100) individuals.<ref name=obrien/> Breeding can occur at any time of year, often prompted by commencement of the dry season or plentiful food.<ref name=hbwFregatidae/>

Frigatebirds have the most elaborate mating displays of all seabirds. The male birds take up residence in the colony in groups of up to thirty individuals.<ref name=hbwFregatidae/> They display to females flying overhead by pointing their bills upwards, inflating their red throat pouches and vibrating their outstretched wings, showing the lighter wing undersurfaces in the process. They produce a drumming sound by vibrating their bills together and sometimes give a whistling call.<ref name=obrien/> The female descends to join a male she has chosen and allows him to take her bill in his. The pair also engages in mutual "head-snaking".<ref name=hbwFregatidae/>

After copulation it is generally the male who gathers sticks and the female that constructs the loosely woven nest. The nest is subsequently covered with (and cemented by) [[guano]]. Frigatebirds prefer to nest in trees or bushes, though when these are not available they will nest on the ground. A single white egg that weighs up to 6–7% of mother's body mass is laid, and is [[Egg incubation|incubated]] in turns by both birds for 41 to 55 days. The [[altricial]] chicks are naked on hatching and develop a white down. They are continuously guarded by the parents for the first 4–6 weeks and are fed on the nest for 5–6 months.<ref name=obrien/> Both parents take turns feeding for the first three months, after which the male's attendance trails off leaving the mother to feed the young for another six to nine months on average.<ref name=hbwFregatidae/> The chicks feed by reaching their heads in their parents' throat and eating the part-regurgitated food. It takes so long to rear a chick that frigatebirds generally breed every other year.<ref name=obrien/>
[[File:Seabird colony.JPG|thumb|right|Seabird colony with great frigatebirds, [[red-tailed tropicbird]], [[red-footed booby|red-footed boobies]], sooty terns and [[black noddy|black noddies]], French Frigate Shoals]]
The duration of parental care in frigatebirds is among the longest for birds, rivalled only by the [[southern ground hornbill]] and some large [[Accipitridae|accipitrids]].<ref>{{cite book |last1=Skutch |first1=Alexander Frank |last2=Gardner |first2=Dana (illustrator) |year=1987 |title=Helpers at Birds' Nests : a worldwide survey of cooperative breeding and related behaviour |pages=[https://archive.org/details/helpersatbirdsne00skut_0/page/69 69–71] |place=Iowa City |publisher=University of Iowa Press |isbn=0-87745-150-8 |url-access=registration |url=https://archive.org/details/helpersatbirdsne00skut_0/page/69 }}</ref> Frigatebirds take many years to reach sexual maturity. A study of great frigatebirds in the Galapagos Islands found that they only bred once they have acquired the full adult plumage. This was attained by female birds when they were eight to nine years of age and by male birds when they were ten to eleven years of age.<ref name=valle>{{cite journal | last1=Valle | first1=Arlos A. | last2=de Vries | first2=Tjitte | last3=Hernández | first3=Cecilia  | year=2006 | title=Plumage and sexual maturation in the Great frigatebird ''Fregata minor'' in the Galapagos Islands | journal=Marine Ornithology | volume=34 | pages=51–59 | url=http://www.marineornithology.org/PDF/34_1/34_1_51-59.pdf }}</ref>

===Feeding===
[[File:Frigate sooty.JPG|right|thumb|An immature great frigatebird snatching a [[sooty tern]] chick]]
Frigatebirds' feeding habits are [[Pelagic birds|pelagic]], and they may forage up to 500&nbsp;km (310&nbsp;mi) from land. They do not land on the water but snatch prey from the ocean surface using their long, hooked [[beak|bills]].<ref name=obrien>{{cite book |last1=O'Brien |first1=Rory M. |year=1990 |chapter=Family Fregatidae frigatebirds |editor1-last=Marchant |editor1-first=S. |editor2-last=Higgins |editor2-first=P.G. |title=Handbook of Australian, New Zealand & Antarctic Birds. Volume 1: Ratites to ducks; Part B, Australian pelican to ducks |place=Melbourne, Victoria |publisher=Oxford University Press |isbn=978-0-19-553068-1 |page=912 |chapter-url=http://nzbirdsonline.org.nz/sites/all/files/142_Great%20Frigatebird.pdf#2}}</ref> They mainly catch small fish such as [[flying fish]], particularly the genera ''[[Exocoetus]]'' and ''[[Cypselurus]]'', that are driven to the surface by predators such as [[tuna]] and [[dolphinfish]],<ref name=weimerskirch03/> but they will also eat [[cephalopod]]s, particularly [[squid]].<ref name=obrien/> [[Menhaden]] of the genus ''[[Brevoortia]]'' can be an important prey item where common, and [[jellyfish]] and larger [[plankton]] are also eaten. Frigatebirds have learned to follow fishing vessels and take fish from holding areas.<ref name=hbwFregatidae/> Conversely tuna fishermen fish in areas where they catch sight of frigatebirds due to their association with large marine predators.<ref name="Weimerskirch 2010">{{cite journal|last1=Weimerskirch|first1=Henri|last2=Le Corre |first2=Matthieu |last3=Kai |first3=Emilie Tew |last4=Marsac |first4=Francis|date=2010|title=Foraging movements of great frigatebirds from Aldabra Island: Relationship with environmental variables and interactions with fisheries|journal=Progress in Oceanography|volume=86|issue=1–2|pages=204–13|doi=10.1016/j.pocean.2010.04.003|bibcode=2010PrOce..86..204W}}</ref> Frigatebirds also at times prey directly on eggs and young of other seabirds, including boobies, petrels, [[shearwater]]s and terns, in particular the [[sooty tern]].<ref name=hbwFregatidae/>

Frigatebirds will rob other [[seabird]]s such as boobies, particularly the [[red-footed booby]], [[tropicbird]]s, shearwaters, petrels, terns, [[gull]]s and even [[osprey]]s of their catch, using their speed and manoeuvrability to outrun and harass their victims until they regurgitate their stomach contents. They may either assail their targets after they have caught their food or circle high over seabird colonies waiting for parent birds to return laden with food.<ref name=hbwFregatidae/> Although frigatebirds are renowned for their [[Kleptoparasitism|kleptoparasitic feeding behaviour]], kleptoparasitism is not thought to play a significant part of the diet of any species, and is instead a supplement to food obtained by hunting.<ref name = "Burger">{{cite book | last1=Schreiber | first1=Elizabeth A. | last2=Burger |first2=Joanne |year=2001 |title=Biology of Marine Birds | place=Boca Raton, Florida | publisher=CRC Press | isbn=0-8493-9882-7}}</ref> A study of great frigatebirds stealing from [[masked booby|masked boobies]] estimated that the frigatebirds could at most obtain 40% of the food they needed, and on average obtained only 5%.<ref>{{cite journal | last1=Vickery | first1=J.A.  | last2=Brooke | first2=M. de L. |year=1994 |title=The kleptoparasitic interactions between Great Frigatebirds and Masked Boobies on Henderson Island, South Pacific | journal=Condor |volume=96 | issue=2 | pages=331–40 | jstor=1369318 | url=http://sora.unm.edu/sites/default/files/journals/condor/v096n02/p0331-p0340.pdf |doi=10.2307/1369318}}</ref>

Unlike most other seabirds, frigatebirds drink freshwater when they come across it, by swooping down and gulping with their bills.<ref name=hbwFregatidae/>

===Parasites===
Frigatebirds are unusual among seabirds in that they often carry blood parasites. Blood-borne [[protozoa]] of the genus ''[[Haemoproteus]]'' have been recovered from four of the five species.<ref>{{cite journal |author1=Merino, Santiago |author2=Hennicke, Janos |author3=Martínez, Javier |author4=Ludynia, Katrin |author5=Torres, Roxana |author6=Work, Thierry M. |author7=Stroud, Stedson |author8=Masello, Juan F. |author9=Quillfeldt, Petra |date=2012 |title=Infection by Haemoproteus parasites in four species of frigatebirds and the description of a new species of Haemoproteus (Haemosporida: Haemoproteidae) |journal=Journal of Parasitology |volume=98 |issue=2 |pages=388–97 |url=http://www.nwhc.usgs.gov/hfs/Globals/Products/MerinoEA2012HaemoproteusFrigates.pdf |doi=10.1645/GE-2415.1 |pmid=21992108 |s2cid=3846342 |access-date=2015-05-14 |archive-url=https://web.archive.org/web/20161210091542/https://www.nwhc.usgs.gov/hfs/Globals/Products/MerinoEA2012HaemoproteusFrigates.pdf |archive-date=2016-12-10 |url-status=dead }}</ref> Bird lice of the [[ischnocera]]n genus ''[[Pectinopygus]]'' and [[amblycera]]n genus ''[[Colpocephalum]]'' and species ''[[Fregatiella aurifasciata]]'' have been recovered from magnificent and great frigatebirds of the Galapagos Islands. Frigatebirds tended to have more parasitic lice than did boobies analysed in the same study.<ref>{{cite journal|author1=Rivera-Parra, Jose L. |author2=Levin, Iris I. |author3=Parker, Patricia G. |date=2014|title=Comparative ectoparasite loads of five seabird species in the Galapagos Islands|journal=Journal of Parasitology|volume=100|issue=5|pages=569–77|doi=10.1645/12-141.1|pmid=24911632|s2cid=9735489 }}</ref>

A heavy chick mortality at a large and important colony of the magnificent frigatebird, located on [[Îles du Connétable|Île du Grand Connétable]] off French Guiana, was recorded in summer 2005. Chicks showed nodular skin lesions, feather loss and corneal changes, with around half the year's progeny perishing across the colony. An [[Alphaherpesvirinae|alphaherpesvirus]] was isolated and provisionally named ''Fregata magnificens'' herpesvirus, though it was unclear whether it caused the outbreak or affected birds already suffering malnutrition.<ref name="de Thoisy">{{cite journal|author1=de Thoisy, Benoit |author2=Lavergne, Anne |author3=Semelin, Julien |author4=Pouliquen, Jean-François |author5=Blanchard, Fabian |author6=Hansen, Eric |author7=Lacoste, Vincent |date=2009 |title=Outbreaks of disease possibly due to a natural avian herpesvirus infection in a colony of young magnificent frigatebirds (''Fregata magnificens'') in French Guiana|journal= Journal of Wildlife Diseases|volume=45|issue=3|pages=802–07|pmid=19617492 |doi=10.7589/0090-3558-45.3.802|s2cid=13466300 |url=https://archimer.ifremer.fr/doc/2009/publication-6811.pdf }}</ref>