Fork-tailed storm petrel

The fork-tailed storm petrel was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the petrels in the genus Procellaria and coined the binomial name Procellaria furcata. Gmelin based his description on the "fork-tailed petrel" that had been described in 1785 in separate publications by the English ornithologist John Latham and the Welsh naturalist Thomas Pennant. It is now one of 18 species placed in the genus Hydrobates that was erected in 1822 by the German zoologist Friedrich Boie. The genus name combines the Ancient Greek hudro- meaning "water-" with batēs meaning "walker". The specific epithet furcatus is Latin meaning "forked". Two subspecies are recognized: However, no molecular genetic analysis has been conducted to discern the two subspecies. == Description ==

The fork-tailed storm petrel is small seabird that is 20 cm in length with a wingspan of 46 cm. Males and females are generally very similar in colour and size. Juveniles also resemble adults with the exception of having a less noticeable notch in their tails. == Distribution and habitat ==

The range of the fork-tailed storm petrel is estimated to cover 22,400,000 km2 with over 6,000,000 individuals occurring globally, making it the second-most widespread and abundant storm petrel. During the breeding season, the fork-tailed storm petrel form dense colonies on islands throughout northern California, Oregon, Washington, British Columbia, Alaska, and northeast Asia off the Kamchatka Peninsula. Their nesting habitat varies, ranging from bare rock to forests. They typically build their nests under rock crevices or roots, or burrow into soft ground with low-growing vegetation. Sparse sightings also indicate that they forage as far south as Hawaii. == Behaviour ==

Food and feeding Like other storm petrels, the fork-tailed storm petrel mainly feeds on crustaceans and fish near the surface of the ocean, including amphipods, myctophids, shallow-water fish (such as greenling and sablefish), copepods, decapods, and squid. They are also extremely opportunistic and can be seen scavenging on fatty tissue of dead marine mammals and also trailing behind fishing boats. and may occasionally dive to depths of 0.6 m. Breeding Like other species, fork-tailed storm petrels spend most of their time out at sea and only return to land to breed around late March to early April. To avoid predation and harassment by gulls, these birds only enter the colony at night and depart before sunrise. and both parents will incubate it for around 50 days. Once able to thermoregulate for itself, the parents then leave the chick, only returning to feed it one every one to four nights. Living in areas with severe climatic conditions, fork-tailed storm petrels have many adaptations to ensure breeding success. Eggs can be left unattended up to 7 days and still successfully hatch, whereas chick growth rates can be adjusted to being faster or slower depending on food supply, rather at a constant rate like many other birds. Interspecific interactions The fork-tailed storm petrel is often the sole prey item for predators early in the breeding season because they return to these remote islands long before any other seabirds. gulls, Further, introduced predators such as foxes, martens, and raccoons have a significant impact on breeding populations. To defend themselves, fork-tailed storm petrels can eject their stomach oil at an incoming threat. == Human impacts and conservation ==

Being widespread and abundant, the fork-tailed storm petrel is not threatened with extinction. However, humans impact their life history in many ways. As a species that feeds on surface material and follows ships, this storm petrel often ingests oil and plastic with their food items. Plastics also do not severely affect the birds because they can be regurgitated after ingestion. In contrast, being a top marine predator, fork-tailed storm petrels are susceptible to bioaccumulation. High lead concentrations have been found in the bones of petrels, and DDT can cause eggshells to become dangerously thin. The greatest threats that face fork-tailed storm petrels today are global climate change and introduced species. An increased severity of storms makes foraging more dangerous, decreasing the chances that an adult will return to the colony. The introduction of mammals also adversely affect storm petrels, where raccoons and river otters prey upon nests, and rabbits increase soil erosion and compromise the structural integrity of burrows. ==References==