Artist's rendition of a gestating female Curabitur Bird.

Curabitur Birds (Curabis natans) are a species of large quasi-avian entities present throughout much of the Backrooms, particularly in levels where Deathmoth colonies are present. They are the only known entity to prey exclusively on Deathmoths, and as such are quite beneficial to humans in the levels they inhabit.

Anatomy and Behavior

The Curabitur Bird's body is significantly reduced compared to the average Earth bird, with a number of organs and other structures entirely missing from their internal anatomy.¹ Their forelimbs are short and featherless, used only for basic movement and maintaining blood flow. Despite the size of their eyes, these entities have quite poor vision, relying mainly on chemoreceptors in their mouth to detect their surroundings. The species exhibits moderate sexual dimorphism, with females usually growing much larger than males; the largest known female Curabitur was measured to be 81 cm tall.²

To survive and hunt, Curabitur Birds possess a number of specialized structures on their bodies, the most prominent of which is the large translucent hump protruding from its back. The organ within, commonly called a "floatsac," contains a semi-solid substance which allows the creature to float through the air in almost any environment while exerting minimal energy. Additionally, their legs are elongated with enlarged muscles, sporting a single hooked claw at the end and two reduced claws on the tarsometatarsus.³ The entity's beak is oriented horizontally and is unable to fully close; dangling from between its mandibles is a modified prehensile tongue that contains a small pocket of bioluminescent gel from the floatsac.

Curabiturs are solitary creatures that, because of their ability to hover, live extremely sedentary lives, traveling only for reproduction or feeding. To move, they will fling their tiny arms backward to displace air, pushing themselves a few centimeters forward with each flap.

Hunting

Curabitur Birds are generally harmless to wanderers, actively avoiding human settlements and only attacking people when threatened or provoked. Most often, they pose a danger only to Deathmoths, as the birds engage in sophisticated hunting techniques to catch and eat them.

To begin, a Curabitur Bird uses the chemoreceptors in its mouth to identify male Deathmoth pheromones, and gradually migrates in the direction of the moth producing them. Once close enough, the bird begins to move its glowing tongue around, emitting a cocktail of pheromones to lure its prey closer. Should it make contact with the tongue, the moth will become caught in the Curabitur's highly adhesive saliva, unable to escape. As it thrashes about, it triggers sensitive hairs on the bird's beak, causing its sharp talons to lurch forward and skewer its prey. Finally, the tongue retracts into the Curabitur's mouth as it begins to feed.

To date there have been no recorded instances of Curabitur Birds preying on female Deathmoths. The leading theory is that the females' sharp mandibles and corrosive spit pose too much risk to the birds, who have evolved to solely target males because of their smaller size and lack of defensive mechanisms. Lending further evidence to this theory, Curabitur pheromones have been observed to only affect male Deathmoths, likely because engaging with the more dangerous females could pose a substantial threat to the entity's life.

Reproduction

The Curabitur reproductive process is highly complex and differs greatly from that of typical avians, as well as nearly all motile animals. It, in fact, more closely resembles the reproduction of plants and fungi, taking place in three stages.

Stage 1: Propagation

• To begin the process, a male Curabitur Bird will release anywhere from fifty to three hundred tiny buds from its floatsac. These "spores," ranging from 8 to 10 mm in diameter, are comprised of a bundle of genetic material coated with a thin layer of luminescent gel. The spores float through the air, carried by subtle changes in pressure, or by wind in levels where natural airflow is present.

Stage 2: Fertilization

• When the spores reach a female Curabitur Bird, they will stick to the outer membrane of her floatsac and slowly pass through the barrier, descending into her inner gel pod. Here they will attach themselves to the organ, and the female will release a sample of her own genetic material which merges with that from the male to form a zygote.

Stage 3: Gestation

• Once fertilized, the embryos will begin to absorb nutrients from the mother's gel pod, gradually growing in size and turning a pale orange hue. After eight days, their limbs and floatsacs will begin to develop as they protrude further outward, resembling smaller spheres on the outside of the mother's hump. Once about three weeks have passed, the baby Curabitur Birds will emerge into the world at approximately 10 cm tall.

Sketch of the Curabitur reproductive process

Unlike most birds, Curabiturs do not care for their offspring. Newborn Curabitur Birds have a significant store of nutrients from their mother's floatsac and are able to subsist on these for the first month of their lives, at which point they will have grown large enough to feed on Deathmoths themselves.

Constellations

On rare occasions, large numbers of Curabitur Birds will congregate for reproduction. These groups are known as "constellations" because their glowing tongues resemble a cluster of stars, and they may be comprised of up to two hundred individuals. Constellations will typically gather for fifteen to twenty days before dispersing, during which time they will seek out Deathmoth colonies and feed on the hive's male population.

These gatherings can devastate even an abundant Deathmoth hive, and in the aftermath the Empress will often flee the hive alongside the remaining females and Praetorians. This can make places previously infested with Deathmoths substantially more habitable, but because constellations are quite uncommon it is not a reliable method of clearing infested areas.

Research and Documentation

The following are entries from the journal of the late Dr. Trescothick, a member of the Backrooms Research Consortium⁴ and the first dedicated researcher of Curabitur Birds. His findings built the foundation for a comprehensive understanding of the entity and its practical benefits.

1 November 1958

As of this morning, we have used the last of the Curabitur Gel from our subject, and we have learned a great deal! Here are our initial findings:

• Slowly absorbs the air around it when exposed, causing it to become spongy and dry. Its full brightness is maintained for roughly three days, but after the gel dries it gradually fades over the course of a few hours.
• Unsuitable for consumption. Incredibly acrid taste and high acidity. (Tested this one myself!)
• Applying it to a surface (smearing) does not diminish its brightness, but shortens its functional period to twelve hours.
• If sealed, it will retain its glow much longer. All of the samples stored in airtight containers are as bright now as they were when I extracted them!
• Can lift small objects into the air, requiring an amount of gel roughly equal to twice the mass of the object. Likely possible with larger objects as well, but the mass requirements make testing infeasible with the samples we currently possess.

I have transferred a drawing from my field sketchbook here and added more notes based on our discoveries.

I am confident that this is just the beginning of the possibilities this entity could grant us, and with the help of my newfound colleagues I am currently searching for more specimens to continue our research.