In November 2021, three juvenile snowy owls have been sighted virtually concurrently in northern Spain. Their extraordinary look and sweetness (white plumage, black spots and enormous amber eyes) attracted numerous ornithologists and curious onlookers. The commonest query was how they may have arrived in Cantabria and Asturias from their distant locations of origin. Had they escaped from someplace? Had they crossed the Atlantic perched on a ship? Now a scientific research reveals that they weren’t born wherever in Spain or central and southern Europe, however in different Arctic latitudes positioned in areas of North America, Greenland, Russia, or Fennoscandia (Sweden, Finland and Norway).
“We can’t pinpoint the situation, however we have now proven that they haven’t escaped from a zoo or from any cage and that they aren’t Spanish or European,” explains biologist Carlos Gutiérrez-Expósito, lead creator of the analysis revealed within the SEO/BirdLife journal Ardeola. It’s probably that they have been born within the wild and obtained misplaced, as this owl “is a long-distance traveler as a result of the resources of the Arctic are ephemeral and unpredictable, which leads them to maneuver south of their traditional vary in winter.”
The researchers analyzed the feathers of two of the three specimens that landed in Spain — a male and a feminine, from whom samples could possibly be taken: the opposite male disappeared — which, as they have been juveniles, had maintained the feathers that grew within the nest the place they have been born.
“They have been stored in a drawer on the College of Cantabria and after I came upon about this I believed that an evaluation of the heavy isotopes could possibly be carried out,” says the biologist. The purpose was to search out out what quantity of deuterium (heavy hydrogen) the feathers contained, as a result of “the additional north the feather was created, the decrease the proportion is, and so we will infer from which latitudes it comes.”
The deuterium content material additionally allowed them to confirm that the 2 specimens analyzed weren’t siblings and that they have been born elsewhere, which additional removes the chance that they’d escaped from someplace.
What’s extra, there are a number of elements that time to the owls’ wild origins: the exhaustion and weight reduction they have been experiencing may have been brought on by a protracted journey (most likely with out meals), along with the problem in adapting to a brand new surroundings. This might have induced the immunosuppression noticed within the male and the sickness within the feminine. Additionally it is not unusual for snowy owls to land on ships on the excessive seas that transport them wherever they go, typically to the European coasts. “Due to this fact, arrival on a ship from North America or Greenland is essentially the most believable origin of the snowy owls present in northern Spain in 2021,” the research states.
The journey of the birds
The primary specimen detected, a male, was discovered exhausted on November 8, 2021, close to the Virgen del Mar seashore, in Santander (Cantabria), and died 4 days later, after being transferred to a restoration middle. The second, a feminine, was sighted in Gozón (Asturias) on November 10. And, three days later, one other male was discovered round three miles away. These final two birds appeared virtually 100 miles from the primary sighting, the research says. The owls remained in Asturias for a number of days, “which attracted a whole bunch of fowl watchers, producing the primary nice rush for a uncommon species in Spain.” They remained there till November 20, to then be sighted additional east: the male in Somo (Cantabria) seven days later and the feminine 13.5 miles additional away, in Santoña (Cantabria) on November 30. “Very near the place the primary exhausted male had been discovered,” the researchers level out.
From there they disappeared, till the male was noticed on the roof of the bullring, close to the port of Santoña, virtually three months after the primary sighting. The group appeared once more, and remained there till dusk. The feminine gave the impression to be in good well being, “displaying regular habits comparable to grooming and defecating, along with her eyes extensive open and alert.” However, the subsequent morning, “she was discovered lifeless,” the research states. She suffered from superior aspergillosis, a illness brought on by a fungus, which she ought to have been accustomed to if she had escaped from someplace close by.
On the time, most hypotheses pointed to the truth that they have been wild specimens that might have arrived on a ship. What strengthened this perception was their simultaneous look in coastal areas near giant cargo ports comparable to Gijón and Santander. As well as, one of many owls had rust on its plumage, one thing frequent on the decks of cargo ships. “Primarily based on these info, the Spanish Rarities Committee accepted the three as wild birds that arrived with the assistance of a ship,” explains the research. However now, the evaluation of secure isotopes gives scientific proof.
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