I have returned from The Galapagos and a most amazing Voyage on the Samba.
The experience was exhilarating, enlightening and enchanting (therefore exhausting) and at some point I shall edit a brief movie/slideshow and post it somewhere for those interested.
Until then, here’s a red-footed booby I encountered on the island of Genovesa where a veritable cornucopia of exotic birds feed, nest and fly about, seemingly unconcerned about human visitors.
Charles Darwin did not visit Genovesa and none of the boobies (blue or red-footed or otherwise) played a role in his Theory of Evolution to my knowledge. They are not endemic or unique to the Galapagos.
The Song Of the Flightless Cormorant
There are many endemic animal species in the Galapagos which likely influenced Darwin’s thinking. On the youngest island,
Fernandina, I encountered the flightless cormorant. The Galapagos cormorant is the only flightless cormorant in existence.
Evolutionary biologist Patricia Parker (who is the senior scientist at the St. Louis Zoo) appears to be the leading researcher on endemic Galapagos bird species. She collected blood from the Galapagos cormorants, searching for mutations that might explain their useless wings.
She and her fellow researchers discovered about a dozen mutated genes in the Galapagos cormorants known to trigger rare skeletal disorders in humans called ciliopathies, often characterized by misshapen skulls, short limbs, and small ribcages. Since Galapagos cormorants have short wings and an unusually small sternum, the researchers suspected this link was significant.
The Sexual Attractiveness of The Male Blue-footed Booby
The blue-footed booby (BFB) is more famous on the Galapagos, primarily because of its mating dance but also because of its fascinating bright blue feet. During the mating dance the male booby prominently displays his sexy feet.
A fascinating study published in 2006 suggests that the brighter the blueness of the male booby feet, the healthier he is and the more likely he is to hook up with a female booby.
When male boobies were food deprived their feet became duller and when re-fed fresh fish the blueness brightened within 48 hours.
Variation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colour, suggesting that carotenoid-pigmentation reveals the immunological state of individuals.
In a second experiment the researchers captured male BFBs after their female mate had laid a first egg and painted a dull blue make-up on the male BFB feet. The females “decreased the size of their second eggs, relative to the second egg of control females, when the feet of their mates were experimentally duller. Since brood reduction in this species is related to size differences between brood mates at hatching, by laying lighter second eggs females are facilitating brood reduction.”
Another study in 2011 found that damage to the DNA of sperm increases with the age of male blue‐footed boobies. Furthermore, like humans sexual attractiveness (foot colour) declines with age in the BFB and is correlated with sperm DNA damage. The authors speculated that. “By choosing attractive males, females might reduce the probability of their progeny bearing damaged DNA.”
I will leave discussions on the technique for acquiring BFB sperm and for applying make-up to their feet to less squeamish authors. In the meantime we can all rest easy with the knowledge that female BFBs like their human counterparts prefer youngish males with brightish blue suede shoes.
(Featured image credit: Cassiano “Zapa” Zaparoli)