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What the sources say

Blue-Footed BoobySula nebouxii

Every figure, record and mechanism on the Blue-Footed Booby profile was written from a source, and this is the working table behind it: 48 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Sula nebouxii (blue-footed booby). Animal Diversity Web, University of Michigan.

The page saysThe sexes are adapted to catch prey of different sizes: the smaller male makes shallow dives, while the heavier female can dive deeper, farther offshore.
The source saysthe male and the female are adapted for catching prey of different sizes. The male, being smaller, performs shallow dives, while the heavier female is able to make deeper dives farther offshore.
The page saysDiving in Sync
The source saysThen the rest of the flock follows the first diving, into the water with perfectly synchronized movements.
The page saysBlue-footed boobies breed on arid islands off the Pacific coasts of tropical America
The source saysThe blue-footed booby breeds on several arid islands off the western coasts of tropical America, Mexico, and northern South America.Note: western coasts of tropical America are its Pacific coasts
The page saysA booby may feed alone, but flocks also hunt together: when one bird spots a fish, it whistles to alert the others, and the rest follow it into the water in perfectly synchronized movements.
The source saysDespite its habit of feeding alone, the blue-footed booby cooperate in flocks to hunt fish. When one bird in the flock spots a fish, it gives a whistle to alert the others. Then the rest of the flock follows the first diving, into the water with perfectly synchronized movements.
The page saysA courting male flaunts his blue feet in an exaggerated high-stepping walk and presents pieces of nest material to the female.
The source saysBreeding begins with elaborate courtship displays by the male. He flies around his territory, flaunting his blue feet in an exaggerated high-stepping walk, and presents pieces of nest material to the female.
The page saysBoth birds also tip their bills to the sky: he gives a piercing whistle, and she answers with groaning calls.
The source saysThen each bird tilts its bill up towards the sky and the male gives a piercing whistle. The female responds with groaning calls, and mating follows shortly afterwards.
The page saysBright blue webbed feet
The source saysa comical-looking tropical seabird with bright blue webbed feetNote: tagline
The page saysa high-stepping courtship walk
The source saysflaunting his blue feet in an exaggerated high-stepping walkNote: tagline
The page saysArid islands
The source saysThe blue-footed booby inhabits arid islands in the Pacific ocean.Note: stats.habitat
The page saysA male flaunts his blue feet in an exaggerated high-stepping walk and presents pieces of nest material to the female.
The source saysHe flies around his territory, flaunting his blue feet in an exaggerated high-stepping walk, and presents pieces of nest material to the female.Note: faq 3
The page saysAfter a courtship flight, he flashes his feet at her as he lands.
The source saysAfter making a courtship flight, the male flashes his feet at the female as he lands.Note: faq 3
The page saysThen both birds tilt their bills to the sky: he gives a piercing whistle, she answers with groaning calls, and mating follows shortly afterwards.
The source saysThen each bird tilts its bill up towards the sky and the male gives a piercing whistle. The female responds with groaning calls, and mating follows shortly afterwards.Note: faq 3
The page saysa male that courts by flaunting his blue feet in an exaggerated high-stepping walk
The source saysBreeding begins with elaborate courtship displays by the male. He flies around his territory, flaunting his blue feet in an exaggerated high-stepping walkNote: vibe.reason

Source
02

Audubon Field Guide, National Audubon Society

Blue-footed Booby. Audubon Field Guide, National Audubon Society.

The page saysFemales measure 80 to 90 centimetres long and weigh 1.5 to 2 kilograms; males are smaller, at 80 to 85 centimetres and 1.2 to 1.6 kilograms.
The source saysFemale — Length: 2 ft 8 in- 2 ft 11 in (80 - 90 cm); wingspan: 5 ft- 5 ft 1 in (1.5 - 1.6 m); weight: 3 lb 11 oz- 4 lb 7 oz (1.5 - 2 kg). Male — Length: 2 ft 7 in- 2 ft 9 in (80 - 85 cm); wingspan: 4 ft 10 in - 5 ft (1.4 - 1.5 m); weight: 2 lb 10 oz- 3 lb 8 oz (1.2 - 1.6 kg).
The page saysin some years small numbers stray north into the southwestern United States, mainly to California's Salton Sea.
The source saysIn some years, small numbers stray north into the southwestern United States, mainly to the Salton Sea, California.

Source
03

Galapagos Conservation Trust

Blue-footed booby. Galapagos Conservation Trust.

The page saysThe Booby That Dive-Bombs at Up to 60 Miles an Hour
The source saysthe bird hits the water at speeds up to 60 mph
The page saysThe blue-footed booby (Sula nebouxii) folds back its wings and plunges: its dives can start more than 20 metres above the water, and it hits the surface at speeds up to 60 miles an hour.
The source saysthe booby folds back its wings, giving it a more streamlined shape, and plunges into the water. Dives may occur from over 20 metres above the water, and the bird hits the water at speeds up to 60 mph
The page saysIts nostrils are permanently closed, which means it can swim underwater easily, and air sacs in its skull protect its brain from the impact of the dive.
The source saysTheir nostrils are permanently closed, meaning they can swim underwater easily, and special air sacs in their skulls protect their brains from the high impact of the dive.
The page saysThe Galapagos Conservation Trust gives an average lifespan of 17 years.
The source saysAverage lifespan: 17 yearsNote: the Trust gives no wild or captive scope, so the page names it; ADW's older AnAge captive average (18 years) was cut in favour of the current institution page
The page saysincluding the Galápagos
The source saysBlue-footed boobies are one of three booby species found on Galapagos.
The page saysThey hunt schools of small fish such as sardines and anchovies, often foraging in groups of up to 200 birds.
The source saysthey take to the sky in search of schools of small fish such as anchovies and sardines, often foraging in large groups of up to 200 birds.
The page saysplunge-dives that hit the water at up to 60 mph.
The source saysplunges into the water. Dives may occur from over 20 metres above the water, and the bird hits the water at speeds up to 60 mphNote: tagline
The page saysoften with rocky coasts, along the eastern Pacific, including the Galápagos
The source saysBlue-footed boobies are one of three booby species found on Galapagos. They are large, distinctive birds, found along the Eastern Pacific coastline where they often nest on small islands with rocky coasts.Note: stats.habitat
The page saysSardines, anchovies, and other small schooling fish
The source saysthey take to the sky in search of schools of small fish such as anchovies and sardinesNote: stats.diet
The page saysplus sealed nostrils and skull air sacs that protect its brain on dives of up to 60 mph.
The source saysthe bird hits the water at speeds up to 60 mph, snapping up fish in its serrated beak. Their nostrils are permanently closed, meaning they can swim underwater easily, and special air sacs in their skulls protect their brains from the high impact of the dive.Note: stats.superpower
The page saysAir sacs in its skull protect its brain from the high impact of a dive that can start more than 20 metres above the water. Its nostrils are also permanently closed, which means it can swim underwater easily.
The source saysDives may occur from over 20 metres above the water ... Their nostrils are permanently closed, meaning they can swim underwater easily, and special air sacs in their skulls protect their brains from the high impact of the dive.Note: faq 2

Source
04

Velando, Beamonte-Barrientos & Torres 2006

Velando, Beamonte-Barrientos & Torres (2006). Pigment-based skin colour in the blue-footed booby: an honest signal of current condition used by females to adjust reproductive investment. Oecologia.

The page saysFeet a Female Reads
The source saysOur data indicate that blue-footed booby females are continuously evaluating their mates
The page saysA male's foot color is both structural, built from arrays of collagen fibres in the skin, and pigment-based, from carotenoids, colored pigments in his food.
The source saysmale foot colour is structurally (collagen arrays) and pigment based. ... Variation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colourNote: the second sentence names the pigment as dietary carotenoids
The page saysA Signal That Shifts in Two Days
The source saysIn 48 h foot colour became duller when males were food deprived and brighter when they were re-fed with fresh fish.
The page saysIn one experiment, males' feet turned duller within 48 hours when they were kept from food, and brighter when they were fed fresh fish again.
The source saysIn 48 h foot colour became duller when males were food deprived and brighter when they were re-fed with fresh fish.
The page saysChanging the carotenoids in their food shifted their immune function and foot color together.
The source saysVariation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colour
The page saysThe researchers suggest the color is a rapid honest signal of a male's current condition.
The source saysThese results suggest that pigment-based foot colour is a rapid honest signal of current condition.Note: 'one that reliably reflects it' glosses 'honest signal' for readers
The page saysIn a second experiment, researchers painted some males' feet a duller blue with make-up the day after the first egg was laid, and their mates laid smaller second eggs than other females.
The source saysOne day after the first egg was laid we captured the males and modified the foot colour of experimental males with a non-toxic and water resistant duller blue intensive make-up, mimicking males in low condition. 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.
The page saysIn this species, brood reduction (the loss of a chick from a nest) is linked to size differences between chicks at hatching, and laying a lighter second egg makes it easier.
The source saysSince 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.Note: the parenthesis glosses the term for readers
The page saysThe researchers say their data indicate that females keep evaluating their mates.
The source saysOur data indicate that blue-footed booby females are continuously evaluating their mates
The page saysBlue feet colored by collagen and carotenoid pigment, which researchers suggest signal a male's current condition
The source saysmale foot colour is structurally (collagen arrays) and pigment based. ... 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. These results suggest that pigment-based foot colour is a rapid honest signal of current condition.Note: stats.superpower
The page saysA male's foot color comes from structural collagen in the skin combined with pigment, including carotenoids from his food.
The source saysmale foot colour is structurally (collagen arrays) and pigment based. ... Variation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colourNote: faq 1
The page saysIn one experiment, males' feet turned duller within 48 hours when they were kept from food, and brighter once they were fed fresh fish again.
The source saysIn 48 h foot colour became duller when males were food deprived and brighter when they were re-fed with fresh fish.Note: faq 1
The page saysChanging the carotenoids in their food shifted immune function and foot color together, suggesting that the color reveals a male's immune state.
The source saysVariation of dietary carotenoids induced comparable changes in cell-mediated immune function and foot colour, suggesting that carotenoid-pigmentation reveals the immunological state of individuals.Note: faq 1
The page saysWhen males' feet were made duller with make-up, their mates laid smaller second eggs, which the researchers say indicates that females keep evaluating their mates.
The source saysOne day after the first egg was laid we captured the males and modified the foot colour of experimental males with a non-toxic and water resistant duller blue intensive make-up, mimicking males in low condition. 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. ... Our data indicate that blue-footed booby females are continuously evaluating their matesNote: faq 1

Source
05

Velando, Drummond & Torres 2006

Velando, Drummond & Torres (2006). Senescent birds redouble reproductive effort when ill: confirmation of the terminal investment hypothesis. Proceedings of the Royal Society B: Biological Sciences.

The page saysA male's breeding success rises at first, then falls steadily with age.
The source saysafter initial increase, male reproductive success declines progressively with age.
The page saysScientists gave males of two age groups a substance that sets off an immune response, which made them seem less likely to survive.
The source saysBefore laying, males of two age classes were challenged with lipopolysaccharide to elicit an immune response, which induced symptoms of declining survival prospects.Note: 'a substance' stands for lipopolysaccharide
The page saysBreeding success dropped in the mature males but rose 98 percent in the old ones.
The source saysReproductive success of immune-challenged mature males fell, while that of immune-challenged old males showed a 98% increase.
The page saysThat fits terminal investment: the idea that animals should put more effort into breeding as they age and their chances of surviving and breeding again decline.
The source saysThis study reports an experimental confirmation of the terminal investment hypothesis, a longstanding theoretical idea that animals should increase their reproductive effort as they age and their prospects for survival and reproduction decline.

Source
06

Sánchez-Macouzet, Rodríguez & Drummond 2014

Sánchez-Macouzet, Rodríguez & Drummond (2014). Better stay together: pair bond duration increases individual fitness independent of age-related variation. Proceedings of the Royal Society B: Biological Sciences.

The page saysBlue-footed boobies have a high divorce rate, but pairs that have been together longer do better.
The source saysa long-lived marine bird with a high divorce rate. ... pair bond duration increases individual fitness
The page saysA study of 24 years of records found that they started their clutches five weeks earlier in the season and raised 35 percent more fledglings (chicks old enough to leave the nest), regardless of age or breeding experience.
The source saysapplying a novel analytical approach to a 24 year database, we found that those pairs which have been together for longer establish their clutches five weeks earlier in the season, hatch more of their eggs and produce 35% more fledglings, regardless of age and reproductive experience.Note: the parenthesis glosses 'fledglings' for readers
The page saysCourtship, Divorce, and Old Age
The source saysa long-lived marine bird with a high divorce rate.Note: courtship and old age are claimed by the ADW and senescent-2006 sentences in this section

Source
07

The IUCN Red List of Threatened Species 2021

Sula nebouxii. The IUCN Red List of Threatened Species 2021: e.T22696683A168988087.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.