On today’s show we learn about the Bahama Nuthatch, a critically endangered avian native to the island of Grand Bahama in the Atlantic Ocean, roughly 60 miles east of the North American mainland off the southern Florida coast.
Rough Transcript
Intro 00:05
Welcome to Bad at Goodbyes.
On today’s show we consider the Bahama Nuthatch
Species Information 02:05
The Bahama Nuthatch is a critically endangered avian native to the island of Grand Bahama in the Atlantic Ocean, roughly 60 miles east of the North American mainland off the southern Florida coast.
The Bahama nuthatch is one of the smallest nuthatches in the world, measuring about 4 inches in length, with a wingspan of about 8 inches and weighing roughly a quarter of an ounce. So tiny, like about the size of teacup and weighing about the same as like 3 pennies.
The Bahama Nuthatch has a brownish cap that extends down to its nape, with a dark brown eye stripe. Its upperparts are predominantly bluish-gray that shift into a chocolate brown at the wingtips. Its chest and belly are a pale white specked with blue gray.
Its black bill is long, pointed and slightly upturned, adapted for probing bark and crevices for insects.
Its tail is short and square.
Its legs and feet are dark gray and its clawed toes are adapted for gripping bark. They’re arranged in a zygodactyl pattern, with two toes facing forward and two facing backward, meaning they can grip and climb up, down, sideways on tree trunks, even gripping and moving upside down.
The Bahama Nuthatch is native to Grand Bahama Island in the Bahamas, specifically the pineyards, a region of Caribbean Pine forests. This is a tropical and subtropical coniferous forest biome, populated with pine trees in the overstory in a warm, humid climate.
The landscape is relatively flat, with occasional limestone outcrops and depressions that create variations in the terrain which may hold seasonal ponds or wetlands during the rainy season. The climate on Grand Bahama Island is subtropical, with warm temperatures and high humidity year-round. Summer temperatures typically reach highs in the 90s °F, while winter temperatures rarely drop below the mid-60s.
The Bahama Nuthatch shares its habitat with Bahama Oriole, Bahama Woodstar, Poisonwood, Bahama Trumpet Tree, Florida Clover Ash, Bahama Warbler, Cuban Emerald Hummingbird, Boas, West Indian Woodpecker, Bahama Pine, Thatch Palm, Buffy Flower Bat, Devil’s Gut, Bahama Yellowthroat, West Indian Snowberry, Rock Iguanas, Southern Bracken Fern, Bushy Beard Grass, Bahama Swallow and many many more.
The Bahama Nuthatch is an obligate resident of these pine woodlands. Obligate resident means that the Bahama Nuthatch is totally dependent on the Caribbean pine and these Caribbean pine forests for its survival, for food, safety from predation, and for reproduction and nesting. It cannot live anywhere else.
The Bahama Nuthatch forages for insects and seeds on all sections of the Caribbean pine, trunk, branches, twigs, and cones, spending most of its time feeding in the upper parts of the tree, roughly 40ft above the forest floor. Methodically moving up and down the trunk (using it’s zygodactyl claws), it peels off loose bark, and probes bark crevices, needle clusters and open cones for seeds and for arthropods like spiders, beetles, roaches, ants, and moths. With harder foods, like hardshelled insects and pine seeds, the nuthatch will hammer repeatedly with its bill until the food is safe for consumption.
It is this behavior that gives the nuthatch family its common name. It opens, or ‘hatches’ nuts, to eat the kernel inside.
Though it has not been directly observed in the Bahama Nuthatch, its two closest relatives, the Pygmy and the Brown-headed Nuthatch are both documented tool-users. They will use twigs, held in their beaks, as a kind of crowbar to pry up bark to search for insects beneath, dropping the twig to feed, when prey is found. Given their close taxonomy and that the Bahama Nuthatch was thought to be a subspecies of the Brown-headed Nuthatch until 2021 we can confidently hypothesize that the Bahama Nuthatch is a tool user too.
Interestingly, one of the key studies that led the establishment of the Bahama Nuthatch as a distinct species was based on their vocalizations. The Bahama Nuthatch communicates using a range of calls, charming described by ornithologists (scientists who study birds) as Chitters, Twitters, Pits, Tinks, Trills and Skew-doos. In two separate 2020 studies, researchers played-back recorded Bahama Nuthatch calls to Brown-headed Nuthatch, and then vice versa. In both cases, acknowledgement and recognition of the calls was very low. And of course acknowledgement and recognition was when the calls were played to their own species was very high. So this behavioral difference along with evidence from genetic studies led the American Ornithological Society to declare the Bahama Nuthatch a distinct species in 2021, believing it diverged roughly half a million years ago.
Researcher David Pereira, in 2018, recorded some of the Bahama Nuthatch’s vocalizations. Let’s drop the music out and take a listen.
SOUND RECORDING
Communication is of course key for avian species and research suggests that nuthatches in particular have really nuanced vocalizations. From a 2020 study of the Red Breasted Nuthatch, Nora Carlson, Erick Greene, and Christopher Templeton found that the nuthatch use distinct alarm calls based on the source and quality of their information. They write:
“Inappropriate responses to a predator threat can be costly either by overestimating the degree of threat leading to wasted time and energy … or by underestimating the degree of threat leading to injury or death from the predator. Thus, natural selection should favour alarm calling systems in which signals reliably reflect the threat level a potential predator poses and receivers assess the quality of the source of the information and base their responses on this information quality.”
So, here’s what that looks like: if a nuthatch observed an approaching predator, they would vocalize a particular alarm call. Alternatively, if they heard another nuthatch’s alarm call, but did not see the threat, they would vocalize a slightly different call indicating that they were like passing along information, that it is not a direct observation. And also the nuthatch will eavesdrop (that is the scientific term) on other birds in their habitat. So, if another species raises an alarm call, a nuthatch that hears it will like translate it, I know that is not the right word but that’s the idea, translate it and vocalize its own alarm but indicating that the concern originated indirectly. So we’re learning that species are encoding substantive information in their vocalization and also that they are assessing what’s called public information from other species, to protect one another from predator threat.
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In the dream, at the end. The memory of sweet downy fledgingings chittering for food. Of the Kirtland’s Warbler visiting every wintertime. And thinking back far now, the mainland, the pines, the home stretching far past where we might ever adventure. Then the storms, the world-enders, the first, the next, the last, sheltering against the impossible wind, alarm muted in the swirling howl. An anxious goodbye, lost, in the dream.
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Bahama Nuthatch mate and lay eggs from November to May. Each breeding season they form monogamous breeding pairs, and it seems likely these bonds last for multiple years, though we do not have enough evidence to say for certain.
They are cavity nesters, excavating holes in dead or decaying Caribbean pine. The female typically selects the nest site, and both partners participate in excavating and modifying the cavity. They line the nest with soft materials like bark fibers, feathers, and pine needles. The female lays a clutch of 3-5 eggs. Incubation lasts about two weeks, and the female does most of the incubating. And the male brings her food during this time.
Upon hatching both parents feed the newborns. The young fledge (means leave the nest) after about three weeks, though continuing to rely on their family for protection and food for roughly another 2-3 weeks.
The Bahama Nuthatch demonstrate cooperative breeding, so like the family unit consists of a breeding pair, their offspring, and potentially one or more helpers, usually male offspring from previous broods. These helpers assist with all aspects of raising the young, from feeding to protection to teaching foraging.
Juvenile Bahama Nuthatch reach reproductive maturity within about a year. But may stay with their parents in this helper role for one or more years before breeding themselves.
We do not have enough information to determine average lifespan, but their close relatives in the nuthatch family live roughly 5 years.
Over the 20th century the Bahama Nuthatch suffered a dramatic population decline due to habitat destruction and introduced predators. Extensive logging of the Caribbean Pine in the mid-20th century, that was then followed by land clearing for development, significantly reduced their habitat. The anthropogenic introduction of invasive predators like corn snakes, house cats, raccoons, and black rats exacerbated the decline.
More recently, human induced climate changed, in the form of more frequent and severe hurricanes, has pushed the Bahama nuthatch population to the very brink. In 2004, there were approximately 1,800 individuals on Grand Bahama Island. Then a series of hurricanes struck the island, felling the caribbean pine and sending saltwater storm surges inland, further damaging the pineyards the nuthatch relies on for food and nesting. Only 23 individuals were spotted in 2007.
Surveys in 2016 in the wake of Hurricane Matthew found no Bahama Nuthatches. But then in 2018, a team of researchers led by Matthew Gardner and David Pereira, who’s recording we heard earlier, over 3 months trekked over 400 miles through the Island’s pine forests and observed 6 individuals.
Then island was hit by Hurricane Dorian in late summer 2019, a Category 5 hurricane causing further damage to the species habitat. We do not know if the Bahama Nuthatch survived.
As far as I could tell from my internet research, no recent large scale observational survey has been initiated, and the bird is tiny, shy, its habitat is relatively remote, so, a very small population could still remain. But it’s been like 5 years, and the birder blogs and recent posts from local naturalists and national park volunteers suggest that the Bahama Nuthatch may be extinct.
The Bahama Nuthatch was first placed on the IUCN Critically Endangered Red List in 2018. Our most recent counts estimate its population is under 10 individuals and it may be extinct.
I’d like to play another of David Pereira’s recordings, as this could be the very last audio capture of the Bahama Nuthatch.
SOUND RECORDING
Citations 24:36
“Abundance and distribution of breeding birds in the pine forests of Grand Bahama, Bahamas” Journal of Caribbean Ornithology; Vol. 24 No. 1 – https://jco.birdscaribbean.org/index.php/jco/article/view/107
Bahamas National Trust – https://bnt.bs/explore/grand-bahama/lucayan-national-park/
Birds of the World from the Cornell Lab of Ornithology – https://doi.org/10.2173/bow.bnhnut2.01
“Further vocal evidence for treating the Bahama Nuthatch Sitta (pusilla) insularis as a species. ” Bulletin of the British Ornithologists’ Club; Vol. 140, No. 4 – https://doi.org/10.25226/bboc.v140i4.2020.a4
IUCN – https://www.iucnredlist.org/species/103881687/181353443
“Land Bird Communities of Grand Bahama Island.” Ornithological Monographs No. 24 – https://doi.org/10.2307/40166704
“Nuthatches vary their alarm calls based upon the source of the eavesdropped signals.” Nature Communication Vol. 11, No. 526 – https://doi.org/10.1038/s41467-020-14414-w
Sound Recording. David Pereira: XC614665 and XC615085, From Xeno-Canto. Accessible at www.xeno-canto.org/614665 and www.xeno-canto.org/615085
“Variation in responses to interspecific vocalizations among sister taxa of the Sittidae.” Avian Conservation and Ecology Vol. 15. Issue 2. Article 15 – http://doi.org/10.5751/ACE-01646-150215
2018 video footage of the Bahama Nuthatch – https://www.youtube.com/watch?v=0eiy6yWxeqA
Wikipedia – https://en.wikipedia.org/wiki/Bahama_nuthatch
Music 27:21
Pledge 34:49
I honor the lifeforce of the Bahama Nuthatch. I will commit its name to my record. I am grateful to have shared time on our planet with this being. I lament the ways in which I and my species have harmed and diminished this species.
And so, in the name of the Bahama Nuthatch I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of plant or animal kin or their habitat, by individuals, corporations, and governments.
I pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.
