Blue-Footed Boobies – Daddy Needs A New Pair Of Shoes
There are five types of boobies which can be seen along the North American coastline today. They are mainly found in the southern states along the Pacific Ocean, with many of them having breeding sites in the Dry Tortugas Islands, which are sand islands just off the shore of the Florida Keys .
Collectively, these are a family of fairly large seabirds. The family also includes other birds, but these five are the ones which will be most likely spotted on the shorelines of the USA this summer.
These are the blue footed booby, red footed booby, brown booby, masked booby and the nazca booby. This time around, we’re going to take a closer look at the blue-footed booby, so buckle up!
NAME: SULA NEBOUXII
BODY LENGTH: 32-35 INCHES
WINGSPAN: 4.9 FEET
WEIGHT: 3.3 POUNDS
CLUTCH SIZE: 1-3 EGGS
INCUBATION PERIOD: 41-50 DAYS
HABITATS: TROPICAL ISLANDS OF PACIFIC OCEAN AND GULF OF MEXICO
BREEDING AGE: 1-6 YEARS (FEMALE) 2-6 YEARS (MALE)
DISTINGUISHING FEATURES: BLUE FEET
COLOR: LIGHT BROWN AND WHITE UNDERBELLY
LONGEVITY: 17 YEARS
DIET: FISH – SARDINES, MACKEREL, ANCHOVIES
SPECIES STATUS: LEAST THREATENED
The blue footed booby is a species you will definitely recognize. If you do spot one on the coastlines of the Pacific this summer, it will probably be stomping about in its fabulously blue colored webbed feet.
The bright blue feet of these famous birds, are due to the carotenoid pigments found in its fishy diet. Research has shown that boobies who have been deprived of food for a couple of days, have substantially duller feet than their well fed counterparts.
But their blue suede shoes are not just for looking pretty – well, actually, they sort of are. Both sexes find the allure and pull of a partner with the brightest colored footwear something of a catch.
Bright blues will be prized over their lackluster counterparts. Research shows that when the male partners had their feet dulled by makeup, the females laid smaller eggs. This suggests they were less willing to invest in the production of egg laying to a less desirable partner.
Similarly, as well as opting to mate with the brighter colored females, a male is more likely to invest time in incubating a smaller egg, laid by a brightly colored female, whereas, the duller footed sister will only get a commitment to any larger egg that they lay.
Clutch sizes are typically two eggs, sometimes three, but sadly the younger chicks are in for a rocky ride. Not so much from a parent – although the blue booby’s parenting style can be described as hands off – but from their big brother/sister!
Boobies, blue boobies included, take sibling rivalry to a whole new level. The older offspring will peck, attack and in some cases simply dispatch the younger hatchling out of the nest, as the parent looks on in apparent disinterest. However, this usually only occurs during periods of food shortages. Other types of boobies are far more murderous (for example the nazca or masked boobies).
But there is evidence that the parents deliberately build their nests with steep enough sides to try and prevent the ejection of their youngest chick. This is in contrast to the masked booby, who has a flat nest and whose chicks almost always kill their younger siblings.
And unlike some other species, the blue footed booby parents will actually attempt to feed their younger chick and not just on the ‘leftover’ basis that some species do – i.e.) they don’t only allow them scraps once their elder sibling has stuffed its beak.
The laying and hatching of the eggs is timed so that they are generally about four days apart in time. This gives the firstborn birds a chance to increase in strength a bit, and to let the parent focus their energies on their newer arrival. It also lessens the chances of both birds being immediately taken by a predator.
Research has shown that perhaps the time gap involved in the hatching of chicks aids the chances of both their survival, as there is likely to be less sibling aggression from the older to the younger.
However, because females are actually larger than male birds, it has been observed that in times of food shortage, the mother is more likely to invest her energies in feeding their male offspring. This is simply because they are likely to be smaller, and therefore require less food.
The blue booby has been noted to try and rectify the imbalance between younger and older chicks. Since subsequent eggs in a clutch are usually smaller and lighter, which means a poorer outcome for the chick, the booby parent will try and feed their younger, smaller offspring. Not all birds, or indeed booby species do this – so perhaps they should be up for some sort of avian parenting award!
Both parents feed their young, with the male bird performing most of the diving needed to obtain food in the early days.
Mackerel, anchovies and sardines make up a large part of the diet of the blue footed booby, and they will often hunt in flocks of up to twelve. One bird will lead the way in the diving party, and then the others will follow.
Boobies dive very impressively, sometimes from as much as three hundred feet in the air. They will then descend into the waters like a bolt, traveling around sixty miles per hour,and reaching depths up to eighty feet.
Despite the pack hunting missions, the blue footed booby prefers to dine alone, taking its prey while they are still underwater.
Male and female boobies hunt and dive slightly differently, based on their differing physiques. The male’s proportionately longer tail makes him the prime diver for suitable infant food, in the early days of chick rearing, as he can dive exceptionally in both deeper, as well as shallow waters.
The females, being the larger of the two, can, however, carry a greater quantity of fish back to the nest. It is thought that the complementary styles of diving, may account for this species greater success in raising two chicks per breeding cycle.
Since half of the population of all blue footed boobies reside in the Galapagos Islands, there was concern in 2014 when a study ascertained that there had been a decline in the number of these birds.
Although still classified as not being endangered, it was discovered that there was a problem with breeding. Although the causes of this are not completely clear, scientists suggest that it is most likely caused by a lack of sardines in the area. Unlike some other species of booby, the blue footed booby’s reproductive success does seem to be more linked to a consumption of sardines.