The reason for our visit to Cap Cotter was to continue Charly Bost’s long-term studies of the macaroni penguins. During our 1-week stay we undertook five separate projects, beginning with attaching GPS loggers and dive time/depth recorders to eight breeding females. Like most crested penguins, macaroni penguins are highly synchronous breeders. In late December most pairs had hatched their single remaining egg (they invariably lose the first egg laid), and the males were brooding the young chicks while the females made a series of short feeding trips to sea. We searched for pairs at a nest with a chick, and identified the female by her clean plumage (the males become soiled from their prolonged stay ashore). We marked the males with dye (to help locate returning females), and carefully attached logging devices to the females’ backs and legs without damaging their feathers. By deploying the devices soon after we arrived at Cap Cotter, we hoped each female would complete two foraging trips before we removed the loggers on or before 26 December, when we started the walk back to Port aux Français. We also attached two tiny new accelerometer dive loggers to two further females, as a trial of new technology. To ensure we were not unduly affecting the birds’ behaviour, we marked a further 20 pairs of birds (not equipped with logging devices) at a nearby sub-colony, and monitored all 30 nest sites every 4 hours during daylight to record when the females were present.
Our second task was to check contents of over 300 nests along transect lines across a large colony, to contribute to long-term monitoring of breeding success. Third was checking about 200 penguins in a defined area of the colony for implanted transponder tags. The birds have no exterior markers applied, and so each individual needed a transponder reader waved over its rump, and a spot of dye applied to show that it had been checked. It sounds quick and easy when you write it! The next development with transponders is installation of an automated aerial array that can be left in place to monitor at a long-term scale the movements of birds between the colony and the sea. The dozens of dye-marked birds allowed Charly to determine the route the study birds used to move to and from the sea. More than a day was spent installing and fine-tuning the buried antennae, and attempting to protect the raised solar panels from lumbering elephant seals.
The final project was collecting blood, breast feathers and tail feathers from 17 immature birds and a similar sample of breeding females, for isotopic analysis. The breast feathers store an isotopic signature of the latitude that the birds were foraging at just before moulting (Jan-Feb for immature birds, a month or two later for breeders), the tail feathers a month or so later (as they continue to grow after the newly-moulted birds return to sea), and the blood shows where they have been feeding in the last month. The study is designed to determine whether young birds use the same foraging areas as adults. It is not feasible to attach GPS loggers to departing chicks, which do not return to the exact location they hatched at. Data loggers need to be retrieved to download the data they store, and so can only be used on birds that will reliably return to the same site for recapture (i.e. breeding adults, in this case).
Our stay at Cap Cotter included Christmas day, and Côme compiled our menu with great enthusiasm, while Charly produced Christmas decorations, candles, and a variety of food and drink treats from a metal box of field gear sent in advance from France.
We ate very well while at Cap Cotter, but our prompt departure from Port aux Français after disembarking from the Marion Dufresne meant that we missed out on bringing fresh fruit and vegetables delivered by the ship. Up until 24 Dec, I did most of the cooking (including skinning and baking a rabbit that Charly snared), but was happy to let my French companions plan and prepare the Christmas eve feast. We started with nuts, olives, chips and camembert (with Ricard aperitif) about 8 pm, and continued feasting until after midnight. Nibbles were followed by pate de foie gras on toast, accompanied by Cremant d’Alsace (method champagnoise), both provided by Charly. The main course was canard à l’orange baked on a bed of marrons (chestnuts), cèpes (wild mushrooms), onions and potatoes, served with cabernet sauvignon. We finished with pears smothered in chocolate sauce (prepared with a splash of single malt – my only contribution). Magnifique!
The Christmas day highlight was an excursion to climb Mont Campbell – the 143 m high sheer-sided volcanic peak 2.5 km south of Cap Cotter. It was a great vantage point to view the extensive plains and numerous lakes of Peninsule Courbet. The top and steep slopes are inaccessible to rabbits, and we saw a few large Pringlea plants (Kerguelen cabbage) and large clumps of Azorella, and harvested handfuls of small-leaved dandelions (introduced) for a green salad. We had another feast for Christmas dinner, though not as elaborate as Christmas eve, finishing with chocolate fondue (with fresh pineapple, dried figs and tinned apricots).
Te Papa curator of vertebrates Dr Colin Miskelly’s participation in seabird research programmes on the French subantarctic island groups of Crozet and Kerguelen was at the invitation of Dr Charly Bost of the CEBC laboratory (Chizé) of CNRS (Centre National de la Recherché Scientifique), France, and was supported by the Institut Polar Français Paul Emile Victor (IPEV) and Te Papa.
Previous blogs in this series
Reunion Island to Crozet Islands
Two days on Ile de la Possession, Crozet Islands
Cap Cotter and the macaroni penguins
Subsequent blogs in this series
The long walk to Port aux Français
A week on Ile Mayes, Iles Kerguelen
The petrels of Ile Mayes, Iles Kerguelen
A week on Ile aux Cochons, Iles Kerguelen
The petrels of Ile aux Cochons, Iles Kerguelen
Love the juxtaposition of technology/penguins and the Christmas feasting.
I am intrigued by the loss of the first egg which Google informs me is not only smaller but deliberately tossed out of the “nest” by the mother when the larger second egg is laid
Seems a strange bit of evolution and a waste of energy
I know in some bird species the strongest nestling throws out the rest and can understand the evolutionary reasons for that but this seems of no value
I deliberately glossed over that point in the blog, and was hoping that no-one would ask! There is no quick or universally accepted answer to your question, and I fear that this reply will set a new length record for a Te Papa blog comment. Please also note that as I am currently in a Mauritian B&B, I do not have many resources at hand to bolster my argument.
I suspect that you are seeking a functional answer for loss of the first egg by macaroni penguins, when the answer may be a dysfunctional one. Evolution by natural selection is not a perfect process, as each step must be based on existing structures, processes and behaviours, rather than starting with a blank canvas and designing the best solution to a problem. Any engineer will tell you that four wheels are faster than six legs on linoleum, yet cockroaches are constrained to incremental increases in leg length and muscle and nerve response times, rather than making the fundamental (and biologically challenging) leap to wheeled locomotion. Perhaps the crested penguins are also trapped in an evolutionary cul-de-sac, with no benevolent creator to wave a magic wand and get rid of that ‘useless’ first egg.
You have obviously researched the topic a bit, but to help others understand what we are talking about, we need some basic knowledge of, and terminology for, penguin breeding ecology (and for crested penguins in particular). Depending on whose taxonomy you follow, there are 19 living species of penguins, with eight species in the genus Eudyptes (crested penguins). It is likely that all penguins evolved from a common ancestor that laid two eggs, as the only species that no longer do so are the king penguin and emperor penguin (both in the genus Aptenodytes), which both lay a single egg. In terms of breeding ecology, the crested penguins fall into two groups. The five smallest species (three species of rockhopper penguins, Snares crested penguin and Fiordland crested penguin) typically hatch both their eggs, and usually (but not always) lose one of their chicks before they are 15 days old. The three largest species (royal penguin, macaroni penguin and erect-crested penguin) typically lose one egg at the start of incubation, and also differ in having the most extreme size difference between their two eggs (of any bird species, not just penguins).
Researchers who study brood reduction in crested penguins refer to the first egg laid as the A-egg, and the second egg as the B-egg. Using the Snares crested penguin as an example, the B-egg is laid 4-5 days after the A-egg, and both eggs hatch around 33 days after the B-egg is laid. In all crested penguins, the B-egg is larger, and is usually the egg that produces any chicks that survive to fledging (though both eggs are fertile, and can produce healthy young). Egg dimorphism is most extreme in the erect-crested penguin, where the B-egg can be up to 138% heavier than the A-egg in the same clutch (and the average difference is 81%).
Eggs require a lot of resources to produce, and from an evolutionary perspective it makes sense to reduce investment in eggs that are less likely to produce surviving young (and ultimately do away with one egg – as the Aptenodytes penguins have ‘succeeded’ in doing). Eggs are also fragile and prone to breaking if knocked around on hard rocks (the preferred nest material for most crested penguins). If we imagine a scenario where 1% of eggs break per day, then the A-eggs are already at a disadvantage, with about 37 days between laying and hatching, compared to 33 days for the B-egg. Under this simple model, 37% of A-eggs would get broken, compared to 33% of B-eggs. And so it makes sense for crested penguins to invest more in the B-egg, which is more likely to hatch. [Strictly they reduce investment in the A-egg, as all crested penguins lay B-eggs that are about 5% of the female’s bodyweight – it is the A-egg that varies in size.] The obvious way to decrease investment in an egg is to use fewer resources in its construction – i.e. lay a smaller egg.
Chicks produced from small eggs are smaller at hatching, and so in those crested penguin nests where both eggs hatch, it is usually the B-chick that out-competes its sibling in the competition to get a belly-full of food from the female (in most crested penguins, the male guards the chick(s) for the first 2 weeks after hatching, while the female makes short foraging trips and feeds the chick(s)).
While it is easy to picture a scenario of decreasing investment in the A-egg, the big question is ‘Why not get rid of it altogether?’ And perhaps the answer is that they can’t. Many birds lay clutches of variable sizes, for example the blackbird in your garden may lay 3-5 eggs per clutch. Smaller clutches are produced when fewer egg follicles develop, and we conceptually think of this as the last 1-2 follicles in a clutch not developing. But could you ever have a scenario where the first follicle does not develop, or is the first follicle needed to get the reproductive hormones and developmental processes necessary for the entire clutch underway?
I suspect that if crested penguins had initially reduced investment in the B-egg, many or most species would now lay single-egg clutches. But the fact that they ‘under-invest’ in A-eggs, yet don’t get rid of them entirely, will ensure ongoing research on one of nature’s great dilemmas for decades to come. Isn’t evolution wonderful?
Thank you for the reply, plenty to ponder there
I guess part of the reason is that evolution while wonderful is not always a matter of steady upward progress but has plenty of dead ends and redundancy
And of course the Macaroni Penguins having the biggest world population may be onto something!
Incidentally I really enjoying your adventures