Editing Western rockhopper penguin (section)

===Variation in foraging behaviour===
Rockhopper penguins are known to have complex foraging behaviors. Influenced by factors such as sea ice abundance, prey availability, breeding stage, and seasonality, rockhopper penguins must be able to adapt their behavior to fit the current conditions.<ref name="Tremblay & Cherel 2003">{{cite journal |last1=Tremblay|last2=Cherel|first1=Yann|first2=Yves|title=Geographic variation in the foraging behaviour, diet and chick growth of rockhopper penguins |journal=Marine Ecology Progress Series|year=2003 |volume=251|pages=279–297|doi=10.3354/meps251279|bibcode=2003MEPS..251..279T|doi-access=free}}</ref> Rockhopper penguins employ different strategies according to their conditions. When making foraging trips, rockhoppers typically leave and return to their colonies in groups. One study showed they are known for going up to {{convert|157|km|||abbr=on}} away from their colonies when foraging.<ref name="Brown 1987">{{cite journal |last1=Brown |first1=Christopher |title=Traveling Speed and Foraging Range of Macaroni and Rockhopper Penguins at Marion Island (Velocidad de Movimiento y Extensión de las Áreas de Forrajeo de los Pingüinos Eudyptes chrysolophus y e. Chrysocome) |journal=Journal of Field Ornithology |year=1987 |volume=58 |issue=2 |pages=118–125 |jstor=4513209 |url=https://www.jstor.org/stable/4513209}}</ref> Females typically forage during the day in 11–12 hour trips consisting of many dives, but they will occasionally forage at night.<ref name="Tremblay & Cherel 2003"/> Night dives are typically much shallower than day dives. Dives typically last around 12h, but can be up to 15hrs, with penguins leaving the colony around dawn (04:00) and returning at dusk (19:00).<ref name="Putz et al 2005">{{cite journal |last1=Putz |first1=Klemens |title=Diving characteristics of southern rockhopper penguins (Eudyptes c. chrysocome) in the southwest Atlantic |journal=Marine Biology |date=November 29, 2005 |volume=149 |issue=2 |pages=125–137 |doi=10.1007/s00227-005-0179-y|s2cid=84393587 }}</ref>

[[File:Rockhopper penguin.jpg|thumb|Rockhopper penguin skeleton in [[Manchester Museum]]]]
Rockhopper penguins employ different strategies and foraging behaviors depending on the climate and environment. A main factor is food location. Subantarctic penguins must dive for longer periods of time and much deeper in search of food than do species in warmer waters where food is more easily accessible.<ref name="Tremblay & Cherel 2003"/>

==== Benthic and pelagic dives ====
Rockhopper penguins are known to employ two different types of dives when foraging, pelagic and benthic dives. Pelagic dives are typically short and relatively shallow and used very frequently. Benthic dives are much deeper dives near the seafloor (up to {{convert|100|m|||abbr=on}} deep)<ref name="Putz et al 2005"/> that typically last longer and have longer bottom time. Penguins performing benthic dives typically only perform a few depth wiggles (changes in depth profile) at their maximum depth.<ref name="Tremblay & Cherel 2000">{{cite journal |last1=Tremblay|last2=Cherel |first1=Yann|first2=Yves |title=Benthic and pelagic dives: a new foraging behaviour in rockhopper penguins |journal=Marine Ecology Progress Series |year=2000|volume=204 |pages=257–267 |doi=10.3354/meps204257|bibcode=2000MEPS..204..257T |doi-access=free }}</ref> at an average speed of range of {{convert|6.9|-|8.1|km/h|m/h}}.<ref name="Brown 1987"/> Although deeper dives tend to be a bit longer than shallow dives, foraging rockhoppers will minimize their travel time when performing benthic dives to gain maximum efficiency. Benthic dives in particular show a stronger correlation to full stomachs than pelagic dives. [[Emperor penguin]]s, [[gentoo penguin]]s, [[yellow-eyed penguin]]s and [[king penguin]]s also use this deep-dive technique to obtain food.<ref name="Tremblay & Cherel 2000"/>

Prey availability is dependent on many factors, such as current climate and conditions of the area. Typically, females will bring back a majority of crustaceans and occasionally some fish for their young. The female's foraging success directly affects chick growth.<ref name="Tremblay & Cherel 2003"/> If food is scarce, females are able to fast for very long periods of time and sometimes will only forage for the chick's benefit.<ref name="Putz et al 2005"/>

==== Dive limitations ====
Because foraging conditions and outcomes are so variable, several factors can limit foraging practices. The timing of breeding, incubation and brooding periods greatly affect foraging time, as females are unable to leave broods for long periods of time.<ref name="Brown 1987"/> Females during the brooding period will follow a much more fixed foraging schedule, leaving and returning to the colony at roughly the same time each day. When not in breeding season, females have much more variability in the length of foraging trips. If females have low energy levels because they are fasting while provisioning chicks, they may make several short foraging trips instead of one longer one.<ref name="Tremblay & Cherel 2003"/>

While benthic dives are efficient and favorable for rockhoppers, they present physiological limitations such as limits in lung capacity, which affects duration of dives. The longest aerobic dive rockhoppers can perform is about 110 seconds long,<ref name="Tremblay & Cherel 2000"/> but dives can last upwards of 180–190 seconds.<ref name="Tremblay & Cherel 2003"/><ref name="Brown 1987"/>