And in new findings that will be published soon — and are enough to turn this working mother’s feet cerulean — scientists have discovered
that the key to a successful long-term booby partnership is the equitable sharing of nest duties year after year.
Such egalitarian couples, said Dr. Sánchez Macouzet, “have reached the sweet spot of cooperation, compatibility
and a willingness to avoid the exploitation of your partner.”
Dr. Drummond and his colleagues have also identified another booby mating pattern
that seems to work nearly as well as a stable long-term partnership and in some ways contradicts it: the May-December effect.
For reasons that remain mysterious, Dr. Drummond said, booby couples in which one bird is young
and the other old often have greater breeding success compared with pairs of the same age.
“They’re superfascinating animals and such a good research model,” said David J. Anderson of Wake Forest
University in Winston-Salem, N. C., who studies both the blue-footed booby and the related Nazca booby.
Should the body mass of the elder nestling decline to 80 percent of normal, however, “it
will increase the daily pecking of its sibling by 500 percent,” Dr. Drummond said.