Darwin’s Vampire Finch – They Are Birds that Drink Blood

Meet the vampire finch, a bird with a taste for blood. With a razor-sharp beak, the finches make small incisions and then lap up the vital fluid. This bloodsucking behavior highlights their remarkable adaptability in isolated ecosystems, proving that nature can find surprising solutions for survival. Let’s find out more interesting facts about these birds.

Vampire finch
Scientific name: Geospiza septentrionalis
Phylum: Mollusca
Class: Cephalopoda
Order: Passeriformes
Family: Thraupidae
Genus: Geospiza

1. Appearance

The vampire finch is a member of the renowned “Darwin’s Finches,” a group of finches consisting of 15 species inhabiting the Galapagos archipelago. Unlike the vampire squid, this bird gets its name from its blood-sucking behavior, which we will discuss later.

This vampire ground finch is a small-sized bird with a wingspan that spans between 4.3 to 4.7 inches (11-12 cm). Exhibiting sexual dimorphism, the males take the lead in size and have predominantly black plumage. On the other hand, the females flaunt a more subdued grayish tone adorned with brown streaks. Fledglings in their immature stage have the appearance of adult females.

Vampire finch characteristic
Vampire ground finch – the bird that drinks blood

These finches sport inky-black eyes adorned with subtle gray eye-rings. Their legs and feet also have the same black hue. What sets the vampire finch apart from other finches is its distinctive elongated beak, gracefully curved with minuscule hooked tips—an adaptation for a feeding ritual unlike any other. Their beak is the most substantial and sharpest among that of the Geospiza difficilis species.

2. They live in islands

The vampire finch can only be found in the Galapagos Archipelago, specifically on the islands of Darwin and Wolf. Located near the equator in the Pacific Ocean, these islands form part of the volcanic tapestry of the Galapagos. The bird thrives in deciduous forests adorned with stretches of low-lying vegetation on Darwin and Wolf Islands, with the majority of its population concentrated in these areas.

Surviving solely on Darwin and Wolf Islands, this species faces the fragile equilibrium between adaptation and extinction. The emergence of a new parasite poses a significant risk to their existence. However, despite their vulnerability, these finches showcase remarkable resilience and a swift capacity for adaptation. They are a typical example of the essence of natural selection of Charles Darwin.

3. They do suck blood

Though it may not catch your eye at first glance, this bird grabs attention with its distinctive feeding habits, leading to its interesting aliases like “vampire ground finch” or simply “vampire finch.” Although this behavior is not restricted to this bird, it is uncommon for a finch.

You can only see this feeding habit only in times of scarcity when fresh water and seeds are in short supply. To make up for their diet, these birds employ their pointed beaks to puncture the skin of bigger birds like the blue-footed boobies or Nazca to suck blood. While this bloodsucking tendency might merely annoy mature birds, it presents a potentially fatal peril to fledgling chicks.

The finches’ shift to blood-drinking is thought to have developed as an adaptation from their initial pecking habits, originally intended for parasite removal from the plumage of boobies.

When foods are abundant, their main diet focus revolves around seeds and insects. Additionally, they eat nectar and bird eggs. To get eggs, they employ a cunning strategy—thrusting their beaks into the earth and using their legs to deftly roll eggs out of the nests of unsuspecting fellow birds.

These finches exhibit this behavior, along with blood-drinking, as proof of their ability to evolve and thrive in the challenging and isolated environment of the Galapagos Islands.

Vampire finches don’t have many predators. Their major enemy is an invasive parasitic fly called the avian vampire fly. These winged intruders target young finches, frequently resulting in their demise.

Fun fact:
On occasion, vampire finch birds engage in the unusual practice of feeding on the blood of their deceased counterparts.

4. Vampire Finch Behavior

These blood-drinking birds live in two islands, each housing a unique group of vampire finches. Each group boasts its own vocalization. The birds of Wolf Island serenade with a lengthy and melodious tune, while their counterparts on Darwin Island opt for a more buzzing melody. In addition to their vocalizations, these species also communicate through whistling sounds.

These finches are sociable. They frequently engage in group foraging and feeding, especially during blood-sucking activities. While these birds exhibit a social disposition, competition may emerge, particularly in regions where various species coexist within the same habitat.

5. Reproduction

Vampire finches are mostly monogamous, sticking with one partner till the end of their lives.
In the mating season, the males become highly territorial. They vigorously defend their nesting territories against intrusions from other species. These males engage in mating behaviors to attract females. They mate and females then lay 2 or 3 eggs within the dome-shaped nests meticulously built among bushes or cactus plants. The females will lay more eggs when rainfall is ample and food resources are abundant.

Vampire finch feeding
The boobies don’t care when vampire finch drinks their blood

The females will incubate their eggs for approximately 13 days. Once the eggs hatch, both parents will feed them insects until they’re ready to leave the nest, which typically takes about 14-15 days. The lifespan of vampire finches can last for about 5 – 10 years. However, this can change, depending on their geographic distribution and food accessibility.

6. Conservation Status

The population of these birds is rapidly decreasing due to the invasion of harmful species such as parasite flies. Although they are categorized as a Vulnerable species on the IUCN Red List, recent studies indicate their current population is becoming relatively stable.

Parasitic flies can wreak havoc on local vampire finch populations that haven’t had the chance to adapt to the fly’s presence, especially on islands like the Galapagos. To deal with the menace of these flies endangering vampire finches, a proposed solution suggests impregnating cotton with insecticide. This specially treated cotton is subsequently offered to the finches for nesting. This can successfully eradicate 100% of parasitic flies in their nests.



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