Diving Behavior and Energetics During Foraging Cycles in King Penguins

Abstract

King Penguins are the second largest of all diving birds and share with their congener, Emperor Penguins, breeding habits strikingly different from other penguins. Our purpose was to determine the feeding behavior, energetics of foraging and the prey species, and compare these to other sympatric species of subantarctic divers. We determined: (1) general features of foraging behavior using time-depth recorders, velocity meters, and radio transmitters, (2) energetics by doubly labeled water, (3) food habits and energy content from stomach lavage samples, and (4) resting and swimming metabolic rate by oxygen consumption measurements.The average foraging cycle was ::::::6 d, during which the mass gain of 30 birds was :::::2 kg. When at sea, the birds exhibit a marked pattern of shallow dives during the night, whereas deep dives of> 100m only occurred during the day. Maximum depth measured from 34 birds and 18 537 dives was 304m, and maximum dive duration from 23 birds and 11 8 7 4 dives was 7. 7 min. The frequency distribution of dive depth was bimodal, with few dives between 40 and 100 m. Overall, swim velocities when a bird was at sea averaged 2.1 m/s (N = 5), while descent and ascent rates of change in depth averaged 0.6 m/s for dives <60 m (N = 74) and 1.4 m/s for dives> 150m (N = 90). Night feeding dives occurred at a rate of :::::20 dives/h, and deep dives occurred at a rate of "'='5 dives/h. The energy consumption rate while resting ashore was 3.3 W/kg (N = 3) or 1.6 times the predicted standard metabolic rate (SMR). The average energy consumption rate while away from the colony was 10 W /kg (N = 8) or 4.6 x SMR, compared to 4.3 x SMR estimated from a time-energy budget. The latter value is based on an average metabolic rate of 4.2 W/kg for three birds while resting in 5°C water and 9.6 W/kg while swimming at 2 m/s, which was extrapolated from the average of three birds swimming at 1 m/s. The average energy intake based on 9 stomach ~ontent samples was nearly 24.6 kJ/g dry mass. The main prey by number are myctophid fish of the species Krefftichthys anderssoni and E/ectrona carlsbergi. It was concluded that: (1) feeding begins "'='28 km from the colony, (2) prey is pursued night and day through its vertical movements, (3) vertical distribution of the prey is reflected closely by diving habits of the birds, (4) deep-diving, for unknown reasons, is an important component of foraging success, (5) diving capacities of King Penguins are remarkable compared to other birds and many pinnipeds, and (6) calculated foraging energetics can be closely estimated from time-energy budgets.

Seasonal importance of oceanic myctophids in king penguin diet at Crozet Islands

“…The 2 former species are among the most abundant mesopelagic fish in the Southern Ocean where they form dense concentrations in the Antarctic Polar Frontal Zone (Sabourenkov 1991), K. anderssoni being also found in oceanic waters surrounding the subantarctic islands (Perissinotto and McQuaid 1992). Prey distribution therefore indicates that birds from Possession Island may forage at that time in 2 distinct areas; 1) in oceanic waters close to the breeding colony, as previously suggested from timedepth recorder data (Kooyman et al 1992), and 2) 300 400 km in the south of the archipelago (where the Polar Front is located; Park et al 1991). Long and distant hunting areas were also indicated by the highly digested nature of the stomach contents in both autumn and spring.…”

Foraging behaviour and reproductive success in Magellanic penguins ( Spheniscus magellanicus ): a comparative study of two colonies in southern Chile

“…There is reason to believe that the diving behaviour of penguins depends on the vertical distribution of their prey (Kooyman et al 1992). However, the opposite case is also possible: the diving behaviour of the predator, determined by extrinsic factors like light conditions under water, could lead to a typical vertical distribution of the prey (Wilson et al 1993b).…”

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

“…Thick-billed murres on St. George have previously been shown to dive to depths no deeper than 5 m during the period of darkness, with dive depths becoming deeper as the sun rose (Takahashi et al, 2008). Shallow night dives most likely reflect a greater abundance of prey in the epipelagic layer due to diel vertical migration (Katugin and Zuev, 2007;Kooyman et al, 1992), lower light conditions for pursuit hunting, or both. A recent Bering Sea study linking observations of murres with the vertical accessibility and availability of their prey clearly shows that murres were conducting shallower dives at night in response to the diel migration of prey (Benoit-Bird et al, 2011).…”