Editing Procellariidae (section)

==Behaviour==
===Food and feeding===
The diet of the procellariids is the most diverse of all the Procellariiformes, as are the methods employed to obtain it. With the exception of the [[giant petrel]]s, all procellariids are exclusively [[ocean|marine]], and the diet of all species is dominated by either fish, [[squid]], [[crustacean]]s and [[carrion]], or some combination thereof.{{sfn|Carboneras|1992a|pp=[https://archive.org/details/handbookofbirdso0001unse/page/223/mode/1up 223–224]}}

The majority of species are surface feeders, obtaining food that has been pushed to the surface by other predators or currents, or have floated in death. Among the surface feeders some, principally the gadfly petrels, can obtain food by dipping from flight, while most of the rest feed while sitting on the water. These surface feeders are dependent on their prey being close to the surface, and for this reason procellariids are often found in association with other predators or oceanic convergences. Studies have shown strong associations between many different kinds of [[seabird]]s, including [[wedge-tailed shearwater]]s, and [[dolphin]]s and [[tuna]], which push shoaling fish up towards the surface.<ref name = "AU"/> The gadfly petrels and the Kerguelen petrel mainly feed at night. In so doing they can take advantage of the nocturnal migration of cephalopods and other food species towards the surface.<ref name=Imber1985/><ref name=Harper1987>{{Cite journal | last=Harper | first=Peter C. | date=1987 | title=Feeding behaviour and other notes on 20 species of Procellariiformes at sea | journal=Notornis | volume=34 | issue=3 | pages=169–192 | url=https://notornis.osnz.org.nz/feeding-behaviour-and-other-notes-20-species-procellariiformes-sea | access-date=2022-01-30 | archive-date=2022-01-30 | archive-url=https://web.archive.org/web/20220130121359/https://notornis.osnz.org.nz/feeding-behaviour-and-other-notes-20-species-procellariiformes-sea | url-status=dead }}</ref>

The fulmarine petrels are generalists, which for the most part take many species of fish and crustacea. The giant petrels, uniquely for Procellariiformes, will feed on land, eating the carrion of other seabirds and [[pinniped|seals]]. They will also attack the chicks of other seabirds. The diet of the giant petrels varies according to sex, with the females taking more [[krill]] and the males more carrion.<ref name=j20/> All the fulmarine petrels readily feed on fisheries discards at sea, a habit that has been implicated in (but not proved to have caused) the expansion in range of the northern fulmar in the Atlantic.<ref>{{Cite book | last=Thompson | first=P.M. | chapter=Identifying drivers of change: did fisheries play a role in the spread of North Atlantic fulmars? | editor1-last=Boyd | editor1-first=I.L. | editor2-last=Wanless | editor2-first=S. | editor3-last=Camphuysen | editor3-first=C.J. | date=2006 | title=Top Predators in Marine Ecosystems: Their Role in Monitoring and Management | series=Conservation Biology | location=Cambridge, England |publisher=Cambridge University Press | isbn=978-0-521-61256-2 | pages=143–156 | archive-url=https://web.archive.org/web/20060823131229/http://www.abdn.ac.uk/zoology/lighthouse/documents/Thompson_fulmars.pdf | archive-date=2006-08-23 | chapter-url=http://www.abdn.ac.uk/zoology/lighthouse/documents/Thompson_fulmars.pdf}}</ref>
[[Image:Broad billed prion.jpg|thumb|The [[broad-billed prion]] (''Pachyptila vittata)'' filters zooplankton from the water with its wide bill. | alt=Photo of a broad-billed prion on land]]

The three larger prion species have bills filled with [[Lamellae (zoology)|lamellae]], which act as filters to sift [[zooplankton]] from the water. Water is forced through the lamellae and small prey items are collected. This technique is often used in conjunction with a method known as hydroplaning where the bird dips its bill beneath the surface and propels itself forward with wings and feet as if walking on the water.<ref name=j6/>{{sfn|Carboneras|1992a|p=[https://archive.org/details/handbookofbirdso0001unse/page/223/mode/1up 223]}}

The diving petrels and many of the shearwaters are proficient divers. While it has long been known that they regularly dive from the surface to pursue prey, using their wings for propulsion,{{sfn|Warham|1990|p=199}} the depth that they are able to dive to was not appreciated (or anticipated) until scientists began to deploy maximum-depth recorders on foraging birds. Studies of both long-distance migrants such as the sooty shearwater and more sedentary species such as the [[black-vented shearwater]] have shown maximum diving depths of {{convert|67|m|ft|abbr=on}} and {{convert|52|m|ft|abbr=on}}.<ref name=j5/><ref>{{Cite journal | last1=Navarro | first1=J. | last2=Votier | first2=S.C. | last3=Phillips | first3=R.A. | date=2014 | title=Diving capabilities of diving petrels | journal=Polar Biology | volume=37 | issue=6 | pages=897–901 | doi=10.1007/s00300-014-1483-0 | doi-access=free | bibcode=2014PoBio..37..897N | hdl=10261/108735 | hdl-access=free }} Supplementary Material.</ref> Tropical shearwaters, such as the wedge-tailed shearwater and the [[Sargasso shearwater]], also dive in order to hunt, making the shearwaters the only tropical seabirds capable of exploiting that ecological niche (all other tropical seabirds feed close to the surface).<ref name=j4/> Many other species of procellariid, from [[white-chinned petrel]]s to [[slender-billed prion]]s, dive to a couple of metres below the surface, though not as proficiently or as frequently as the shearwaters.<ref name=j3/>

===Breeding===

====Colonies====
[[Image:Kappensturmtaucher.jpg|thumb|The colonies of the [[greater shearwater|great shearwater]] (''Ardenna gravis'') are among the densest of any procellariid, with 1 pair per m<sup>2</sup>. | alt=Photo of a great shearwater in flight ]]
The procellariids are colonial, nesting for the most part on islands. These colonies vary in size from over a million birds to just a few pairs, and can be densely concentrated or widely spaced. At one extreme the [[greater shearwater]] nests in concentrations of one pair per square metre in three colonies of more than one million pairs,{{sfn|Brooke|2004|p=28}} whereas the giant petrels nest in clumped but widely spaced territories that barely qualify as colonial. Colonies are usually located near the coast, but some species nest far inland and even at high altitudes. [[Hutton's shearwater]] (''Puffinus huttoni'') breeds in burrows on the sea-facing mountainside of the [[Kaikōura Ranges|Kaikoura Ranges]] on [[South Island]], New Zealand. The colonies are {{cvt|1200|-|1800|m}} above sea level at a distance of {{cvt|12|-|18|km}} from the coast.<ref>{{cite book | year=1990 | chapter=''Puffinus huttoni'' Hutton's Shearwater| 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 A, Ratites to petrels | location=Melbourne, Victoria | publisher=Oxford University Press | isbn=978-0-19-553068-1 | pages=657–662 | chapter-url=https://nzbirdsonline.org.nz/sites/all/files/111_Hutton's%20Shearwater.pdf }}</ref><ref>{{Cite journal | last1=Sommer | first1=E. | last2=Bell | first2=M. | last3=Bradfield | first3=P. | last4=Dunlop | first4=K. | last5=Gaze | first5=P. | last6=Harrow | first6=G. | last7=McGahan | first7=P. | last8=Morrisey | first8=M. | last9=Walford | first9=D. | last10=Cuthbert | first10=R. | date=2009 | title=Population trends, breeding success and predation rates of Hutton's Shearwater (''Puffinus huttoni''): A 20 year assessment | journal=Notornis | volume=56 | issue=3 | pages=144–153 | url=https://notornis.osnz.org.nz/system/files/Notornis_56_3_144.pdf | access-date=2022-01-22 | archive-date=2022-01-21 | archive-url=https://web.archive.org/web/20220121205539/http://notornis.osnz.org.nz/system/files/Notornis_56_3_144.pdf | url-status=dead }}</ref> Other exceptions are [[Barau's petrel]] (''Pterodroma baraui'') that breeds at {{cvt|2700|m}} on the island of [[Réunion]] in the Indian Ocean,<ref>{{Cite journal | last1=Bretagnolle | first1=Vincent | last2=Attié | first2=Carole | date=1991 | title=Status of Barau's Petrel (''Pterodroma baraui''): colony sites, breeding population and taxonomic affinities | journal=Colonial Waterbirds | volume=14 | issue=1 | pages=25–33 | doi=10.2307/1521275 | jstor=1521275 }}<!-- Table 1 lists high-nesting Procellariiformes--></ref> and the snow petrel (''Pagodroma nivea'') that breeds in Antarctica on mountain ledges up to {{cvt|400|km}} from the open sea.<ref>{{cite book | year=1990 | chapter=''Pagodroma nivea'' Snow Petrel | 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 A, Ratites to petrels | location=Melbourne, Victoria | publisher=Oxford University Press | isbn=978-0-19-553068-1 | pages=402–410 | chapter-url=https://nzbirdsonline.org.nz/sites/all/files/068_Snow%20Petrel.pdf | access-date=2022-01-22 | archive-date=2022-11-02 | archive-url=https://web.archive.org/web/20221102021333/https://nzbirdsonline.org.nz/sites/all/files/068_Snow%20Petrel.pdf | url-status=dead }}</ref><ref>{{ cite journal | last1=Goldsworthy | first1=P.M. | last2=Thomson | first2=P.G. | date=2000 | title=An extreme inland breeding locality of snow petrels (''Pagodroma nivea'') in the southern Prince Charles Mountains, Antarctica | journal=Polar Biology | volume=23 | issue=10 | pages=717–720 | doi=10.1007/s003000000146 | doi-access= | bibcode=2000PoBio..23..717G | s2cid=21493380 }}</ref>

Most seabirds are colonial, and the reasons for colonial behaviour are assumed to be similar, if incompletely understood by scientists. Procellariids for the most part have weak legs and are unable to easily take off, making them highly vulnerable to [[mammal]]ian predators. Most procellariid colonies are located on islands that have historically been free of mammals; for this reason some species cannot help but be colonial as they are limited to a few locations to breed. Even species that breed on continental Antarctica, such as the [[Antarctic petrel]], are forced by habitat preference (snow-free north-facing rock) to breed in just a few locations.{{sfn|Brooke|2004|pp=28–31}}

[[Image:Christmas shearwater.jpg|thumb|left|[[Christmas shearwater]]s (''Puffinus nativitatis'') are one of the surface-breeding procellariids. Here a pair engages in some mutual preening. | alt=Photo of a pair of Christmas shearwaters on land under vegetation]]

Most procellariids' nests are in burrows or on the surface on open ground, with a smaller number nesting under the cover of vegetation (such as in a forest). All the fulmarine petrels bar the snow petrel nest in the open, the snow petrel instead nesting inside natural crevices. Of the rest of the procellariids the majority nest in burrows or crevices, with a few tropical species nesting in the open. There are several reasons for these differences. The fulmarine petrels are probably precluded from burrowing by their large size (the crevice-nesting snow petrel is the smallest fulmarine petrel) and the high latitudes they breed in, where frozen ground is difficult to burrow into. The smaller size of the other species, and their lack of agility on land, mean that even on islands free from mammal predators they are still vulnerable to [[skua]]s,<ref name=j21/> [[gull]]s and other avian predators, something the aggressive [[stomach oil|oil]]-spitting fulmars are not. The chicks of all species are vulnerable to predation, but the chicks of fulmarine petrels can defend themselves in a similar fashion to their parents. In the higher latitudes there are thermal advantages to burrow nesting, as the temperature is more stable than on the surface, and there is no [[wind-chill]] to contend with. The absence of skuas, gulls and other predatory birds on [[tropical]] islands is why some shearwaters and two species of gadfly petrel ([[Kermadec petrel]] and the [[herald petrel]]) can nest in the open. This has the advantages of reducing competition with burrow nesters from other species and allowing open-ground nesters to nest on [[coral]]line islets without soil for burrowing. Procellariids that burrow in order to avoid predation almost always attend their colonies [[nocturnal animal|nocturnally]] in order to reduce predation as well.<ref name=j22/>

Procellariids display high levels of [[philopatry]], exhibiting both natal philopatry and site fidelity. Natal philopatry, the tendency of a bird to breed close to where it hatched, is strong among all the Procellariiformes. The evidence for natal philopatry comes from several sources, not the least of which is the existence of several procellariid species that are endemic to a single island.{{sfn|Brooke|2004|p=111}} The study of [[mitochondrial DNA]] provides evidence of restricted [[gene flow]] between different colonies, and has been used to show philopatry in [[fairy prion]]s.<ref name=j7/> [[Bird ringing]] provides compelling evidence of philopatry; a study of [[Cory's shearwater]]s nesting near [[Corsica]] found that nine out of 61 male chicks that returned to breed at their natal colony actually bred in the burrow they were raised in.<ref name=j8/> This tendency towards philopatry is stronger in some species than others, and several species readily prospect potential new colony sites and colonise them. It is hypothesised that there is a cost to dispersing to a new site, the chance of not finding a mate of the same species, that selects against it for rarer species, whereas there is probably an advantage to dispersal for species that have colony sites that change dramatically during periods of [[Glacial motion|glacial advance or retreat]]. There are differences in the tendency to disperse based on sex, with females being more likely to breed away from the natal site.{{sfn|Brooke|2004|pp=112–113}}

====Mate and site fidelity====
[[Image:Fulmarus glacialis 1 8.jpg|thumb|A [[northern fulmar]] (''Fulmarus glacialis'') pair perform a cackling duet. | alt=Photo of a pair of northern fulmar on a rock]]
Procellariids, as well as having strong natal philopatry, exhibit strong site fidelity, returning to the same nesting site, burrow or territory in sequential years. The figure varies for different species but is high for most species, an estimated 91% for [[Bulwer's petrel]]s.<ref name=j9/> The strength of this fidelity can also vary with sex; almost 85% of male [[Cory's shearwater]]s return to the same burrow to breed the year after a successful breeding attempt, while the figure for females is around 76%.<ref name=j10/> This tendency towards using the same site from year to year is matched by strong [[Monogamy in animals|mate fidelity]], with birds breeding with the same partner for many years; it has been suggested that the two are linked, with site fidelity acting as a means in which partnered birds could meet at the beginning of the breeding season.<ref name=j11/> One pair of [[northern fulmar]]s bred as a pair in the same site for 25 years.{{sfn|Carboneras|1992a|pp=[https://archive.org/details/handbookofbirdso0001unse/page/225/mode/1up 225–226]}} Like the [[albatross]]es the procellariids take several years to reach sexual maturity, though due to the greater variety of sizes and lifestyles, the age of first breeding stretches from two or three years in the smaller species to 12 years in the larger ones.{{sfn|Carboneras|1992a|p=[https://archive.org/details/handbookofbirdso0001unse/page/235/mode/1up 235]}}{{sfn|Carboneras|1992b|p=[https://archive.org/details/handbookofbirdso0001unse/page/275/mode/1up 275]}}

The procellariids lack the elaborate breeding dances of the albatrosses, in no small part due to the tendency of most of them to attend colonies at night and breed in burrows, where visual displays are useless. The fulmarine petrels, which nest on the surface and attend their colonies [[Diurnality|diurnally]], do use a repertoire of stereotyped [[ethology|behaviours]] such as cackling, preening, head waving and nibbling, but for most species courtship interactions are limited to some billing (rubbing the two bills together) in the burrow and the vocalisations made by all species. The calls serve a number of functions: they are used territorially to protect burrows or territories and to call for mates. Each call type is unique to a particular species and indeed it is possible for procellariids to identify the sex of the bird calling. It may also be possible to assess the quality of potential mates; a study of [[blue petrel]]s found a link between the [[rhythm]] and duration of calls and the body mass of the bird.<ref name=j23/> The ability of an individual to recognise its mate has been demonstrated in several species.<ref>{{Cite journal | last=Brooke | first=M. de L. | date=1978 | title=Sexual differences in the voice and individual vocal recognition in the Manx shearwater (''Puffinus puffinus'') | journal=Animal Behaviour | volume=26 | pages=622–629 | doi=10.1016/0003-3472(78)90074-X| s2cid=53262540 }}</ref><ref>{{Cite journal | last1=Bretagnolle | first1=Vincent | last2=Lequette | first2=Benoit | date=1990 | title=Structural variation in the call of the Cory's shearwater (''Calonectris diomedea'', Aves, Procellariidae) | journal=Ethology | volume=85 | issue=4 | pages=313–323 | doi=10.1111/j.1439-0310.1990.tb00410.x| bibcode=1990Ethol..85..313B }}</ref>

====Breeding season====
Like most seabirds, the majority of procellariids breed once a year. There are exceptions; many individuals of the larger species, such as the [[white-headed petrel]], will skip a breeding season after successfully [[fledge|fledging]] a chick, and some of the smaller species, such as the [[Christmas shearwater]]s, breed on a nine-month schedule. Among those that breed annually, there is considerable variation as to the timing; some species breed in a fixed season while others breed all year round. [[Climate]] and the availability of food resources are important influences on the timing of procellariid breeding; species that breed at higher [[latitude]]s always breed in the summer as conditions are too harsh in the winter. At lower latitudes many, but not all, species breed continuously. Some species breed seasonally to avoid competition with other species for burrows, to avoid predation or to take advantage of seasonally abundant food. Others, such as the tropical [[wedge-tailed shearwater]], breed seasonally for unknown reasons. Among the species that exhibit seasonal breeding there can be high levels of synchronization, both of time of arrival at the colony and of lay date.{{sfn|Brooke|2004|pp=46–50}}

Procellariids begin to attend their nesting colony around one month prior to laying. Males will arrive first and attend the colony more frequently than females, partly in order to protect a site or burrow from potential competitors. Prior to laying there is a period known as the pre-laying exodus in which both the male and female are away from the colony, building up reserves in order to lay and undertake the first incubation stint respectively. This pre-laying exodus can vary in length from 9 days (as in the [[Cape petrel]])<ref name=j24/> to around 50 days in [[Atlantic petrel]]s.<ref name=j25/> All procellariids lay a single white egg per pair per breeding season, in common with the rest of the Procellariiformes. The egg is large compared to that of other birds, weighing 6–24% of the female's weight. Immediately after laying the female goes back to sea to feed while the male takes over incubation. Incubation duties are shared by both sexes in shifts that vary in length between species, individuals and the stage of incubation. The longest recorded shift was 29 days by a [[Murphy's petrel]] from [[Henderson Island (Pitcairn Islands)|Henderson Island]]; the typical length of a [[gadfly petrel]] stint is between 13 and 19 days. Fulmarine petrels, shearwaters and prions tend to have shorter stints, averaging between 3 and 13 days. Incubation takes a long time, from 40 days for the smaller species (such as prions) to around 55 days for the larger species. The incubation period is longer if eggs are abandoned temporarily; procellariid eggs are resistant to chilling and can still hatch after being left unattended for a few days.{{sfn|Carboneras|1992a|p=[https://archive.org/details/handbookofbirdso0001unse/page/227/mode/1up 227]}}{{sfn|Carboneras|1992b|p=[https://archive.org/details/handbookofbirdso0001unse/page/262/mode/1up 262]}}

[[Image:Starr 990520-0830 Casuarina equisetifolia.jpg|thumb|The chick of a [[Bonin petrel]] (''Pterodroma hypoleuca'') takes almost three months to fledge. This chick has most of its adult plumage but still retains a considerable amount of down. | alt=Photo of a Bonin petrel chick covered with both feathers and down]]
After hatching the chick is brooded by a parent until it is large enough to [[thermoregulation|thermoregulate]] efficiently, and in some cases defend itself from predation. This guard stage lasts a short while for burrow-nesting species (2–3 days) but longer for surface nesting [[fulmar]]s (around 16–20 days) and [[giant petrel]]s (20–30 days). After the guard stage both parents feed the chick. In many species the parent's foraging strategy alternates between short trips lasting 1–3 days and longer trips of 5 days.<ref name=j26/> The shorter trips, which are taken over the continental shelf, benefit the chick with faster growth, but longer trips to more productive [[pelagic zone|pelagic]] feeding grounds are needed for the parents to maintain their own body condition. The meals are composed of both prey items and [[stomach oil]], an [[food energy|energy]]-rich food that is lighter to carry than undigested prey items.<ref name=j27/> This oil is created in a stomach organ known as a [[proventriculus]] from digested prey items, and gives procellariids and other Procellariiformes their distinctive musty smell. Chick development is quite slow for [[bird]]s, with fledging taking place at around two months after hatching for the smaller species and four months for the largest species. The chicks of some species are abandoned by the parents; parents of other species continue to bring food to the nesting site after the chick has left. Chicks put on weight quickly and some can outweigh their parents, although they will slim down before they leave the nest.<ref name="Maynard">{{cite encyclopedia |last=Maynard |first=B.J.|editor1-first=Michael |editor1-last= Hutchins|encyclopedia=Grzimek's Animal Life Encyclopedia |title=Shearwaters, petrels, and fulmars (procellariidae) |edition=2 |year=2003 |publisher=Gale Group|volume=8 Birds I Tinamous and Ratites to Hoatzins |location=Farmington Hills, MI|isbn=978-0-7876-5784-0 |pages=123–127}}</ref> All procellariid chicks fledge by themselves, and there is no further parental care after fledging. Life expectancy of Procellariidae is between 15 and 20 years; the oldest recorded member was a [[northern fulmar]] that was over 50 years.<ref name="Maynard" />