Our second day in the field was fantastic, we were able to collect samples from 19 penguins which were nesting in a cave off of beach S4. The most challenging part was crawling through the very tight spaces to get deep enough into the cave to access the penguin burrows. Marco, Daniel and Frank maneuvered up and down the dark slippery slope with penguins in hand to the mouth of the cave so that we could examine and collect the necessary samples from them.
The walls of the cave are covered with a dark black and green algae that rubs off on everything that comes into contact with it. The floor of the cave is part guano, part sand and very slippery from the ocean mist that is blown into the mouth of the cave. There are a few vampire bats clinging to the ceiling in the crevices above and Inca terns perched just outside the mouth of the cave on the many little ledges above.About 9 of the penguins we handled today already had metal ID bands on their wings. Biologists have used this identification system for over 10 years to identify and track individual penguins at PSJ. They have many years of data describing which birds are at which nests at which beach. This information along with our health assessment will begin to help us understand the health, breeding success and longevity of the Humboldt penguins at PSJ. It will also help determine
what diseases and nutritional factors influence the health of the population. Four birds we handled today were also sampled last year. Compared to yesterday, the birds from this group of nests had more ectoparasites than those we examined yesterday. These include primarily feather lice and ticks, both of which are species specific but still bite if they happen to make it onto humans. To try to prevent getting bitten by these pesky insects we tuck our pants into socks and use a variety of insect repellent sprays to make sure the bugs stay on the birds and not us. We have seen a correlation between numbers of ectoparasites and nest locations in that the wetter, less desirable nesting areas appear to have birds with more ectoparasites than those from locations in drier locations.Before an adult penguin is removed from the next, specialized tools are used to gently scoop the 1-2 eggs out of the nest so they are not damaged as the adult is lifted out of its burrow. While the adult is being examined, someone holds the eggs in their pockets to make sure they stay warm. The eggs are also numbered with the nest number so that the biologists will be able to determine which eggs hatch and which parents are successful with their breeding efforts.
The most exciting thing in the field this morning was that one of the nests had a chick that was beginning to pip. Pipping refers to when the chick is beginning to hatch. The chick makes a small hole in the shell with its egg tooth (a special projection on the tip of its beak that is only used to get out of the shell and falls off later) and begins to resorb its yolk sac. The chick begins to vocalize and the parents eagerly await the chick’s arrival. Over 24-48 hrs the chick continues to chip away its shell until finally it is able to push itself out of the egg shell. The chick we found this morning was actively vocalizing and had already made a 0.5 cm opening into its shell. Hopefully, a healthy, strong penguin chick will hatch by tomorrow.It was encouraging that all the nests had eggs and that the animals seem healthy. There are periods when the penguins do not fare so well but food seems to be in good supply this year.
We’re off to the lab to process samples and start again first thing tomorrow morning.
Jennifer Langan, DVM, DACZM
Veterinarian – Chicago Zoological Society & University of Illinois
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