Arxiu d'etiquetes: bird of prey

Is it a stork? Is it an eagle? It is… the secretarybird!

Tall and stylish, at first sight the secretarybird reminds us of a stork or a crane: black and white plumage, long legs… but the beak and claws betray it. Beyond that they are all birds, they have little in common. Find out more about this especial bird of prey!

BIRDS OF PREY

Curved and powerful beaks, curved claws, carnivorous feeding… we all know how to recognize an eagle, a vulture, a hawk or an owl when we have them in front of us. Birds of prey, raptors or predatory birds are specialized in hunting live animals, except vultures (which are scavengers) and the palm-nut vulture (Gypohierax angolensis) which feeds, along with other things, on the fleshy husks of oil palm and raffia palm fruits. Raptors sometimes also steal prey from other raptors, hence their name. Once they have killed the prey, they try to avoid the indigestible parts, but it is inevitable that they ingest skin, hair, nails, teeth, bones… all these elements of difficult digestion will be regurgitated out of the beak after a few hours in the shape of a bolus, called pellet.

egagropila
Pellets of some owls and their content. Source

REPRODUCTION

Depending on the species, raptors build the nest on the ground, trees or rocks, except for falconidae and nocturnal raptors which do not build nests (they use those of other species or put their eggs in holes in trees or rocks). As a general rule, the larger ones are sexually mature after several years and lay a single egg, while the smaller ones are sexually mature after a year and lay more than one egg. The females of the hunter raptors are usually larger than the male and unlike the nocturnal ones, in the diurnal raptors the male also participates in the incubation.

SENSES

It is estimated that diurnal birds of prey see up to 8 times more in detail than a human and in color, so they can spot prey or carrion at great distances. By contrast, hearing is the most developed sense of the nocturnal raptors, with a hearing acuity 50 times higher than ours and black and white vision. As in the rest of the birds, the smell is not very good, except for the turkey vulture (Cathartes aura).

THE SECRETARYBIRD: A DIFFERENT BIRD OF PREY

The secretarybird (Sagittarius serpentarius) is of the same order (Accipitriformes) as ospreys, New World vultures, kites, hawks, buzzards and eagles. It is the only representative of the Sagittariidae family. In flight or at a distance, it looks more like a crane than a bird of prey. It has long, bare legs and shorter, not-so-curved fingers.

Secretarybird in Serengeti’s National Park. Photo: Yoky

It has a crest of black feathers. The flight feathers are also black and the rest of the body is gray and whitish, both in males and females. In the center of the tail it has two longer feathers. In males the feathers of the crest are slightly longer. His orange plucked face and its long lashes strongly attract our attention (in young secretarybirds the color is more yellowish than orange-reddish). It can weigh up to 4.5 kg, measure 1.5 m in height (it is the highest and longest raptor) and measure 2.2 m of wingspan.

Up-close of the secreatrybird. Photo: unknown

The origin of his name is not clear: it was believed it was because of the crown of 20 feathers that remind of the feathers attached to the hair of the British secretaries of the nineteenth century, or to the scribes of the Middle Ages, who carried the feathers behind the ear. Most likely, its name derives from a bad French translation of its Arabic name: saqr-et-tair (hunting bird).

FEEDING

Although its diet includes large insects, small mammals, frogs, lizards and turtles, it also preys on snakes, including cobras and vipers.

Secretarybird eating a whole snake. Source

Although it can fly, it prefers walking and running. Unlike most raptors, it does not look for prey from the air. Adults usually hunt in pairs and are able to walk up to 25-30 kms a day through the African savannah in search of their prey. Once a snake is detected, the secretary kicks the grass and pursues it until it catches it. Like all raptors, it does not attack its prey with its beak, but with its claws: first it kills it or stuns it with strong kicks, with an equivalent force of up to 5 times its weight and then swallow it whole (reference). In addition, unlike other birds, it keeps its eyes open during the attack, which allows to hit with precision the head and neck of its prey. Do you remember the cassowary, another bird capable of fatal kicks?

Do not miss this video in which you can see a couple of secretarybirds with their chicks and their impeccable way of hunting in slow motion:

REPRODUCTION

Secretarybirds are quite social. They can live in groups of 2 to 5 individuals, although they may be lonely occasionally. The mating ritual includes undulating flights by the male and falls, together with guttural calls. Male and female also chase each other with open wings similar to when they hunt. They form monogamous couples for life. Mating occurs on the ground and occasionally on the top of the trees, preferably between August and March.

Secretarybird in tis nest with two eggs. Photo: Hispalois

They build the nest in the acacia branches, which they can reuse year after year until it is too heavy. They put from 1 to 3 eggs of greenish-white color in intervals of 2 or 3 days, although the weakest chick usually dies. The eggs are incubated mainly by the female, although the male can participate in the incubation, and lasts about 42-46 days. The chicks will stand up at 6 weeks and after a short time their parents will teach them to hunt. Their plumage is darker and in successive moults they will obtain the color of adults. They will live up to 15 years old at the most in the wild.

Secretarybird chicks. Source

In this video made with a hidden camera in a nest you can observe how the secretary regurgitates the food to feed his chick:

DISTRIBUTION, THREATS AND CONSERVATION

The secretarybird distributes across the savanna and open African pastures (south of the Sahara) and it is not migratory. It is classified as vulnerable by the IUCN Red List and appears in Appendix II of CITES.

Sagittarius serpentarius distribution map
Distribution of the secretarybird. Source: IUCN

Although some individuals live in protected areas such as natural parks, their population is probably declining due to habitat degradation, alteration, poisoning, hunting and capture for trade. The natural predators of chicks are ravens, crows, tocos and hornbills, large owls and kites.

Although traditionally admired in Africa, for its conservation there are proposed measures such as a surveillance program to obtain an estimate of the population and the monitoring of the trend of the species. It is also proposed in the areas where the species is decreasing, to increase the awareness of the threats among the local population, in particular the farmers. There also propositions to face the capture and trade of the species.

As a final curiosity, the secretary is the emblem of the Republic of Sudan, it appears on the coat of arms of South Africa and on many stamps of different African countries.

Sudan emblem. Source

 

South Africa coat of arms. Source

REFERENCES

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5 experiences in a wildlife rescue center

If you’re a former, present or future biology student this interests you. One of the most rewarding work experiences I ever had was working in a wildlife rescue center. Actually, I worked as a technical assistant veterinary, but allowed me to know how a center like this (led by a biologist) works and have direct contact with wildlife. These are just 5 experiences and lessons learned from that adventure.

WHAT IS A WILDLIFE RECOVERY CENTER?

It is a center where sick or injured wild animals are welcome where they have veterinary care and food until they are able to fend for themselves. Then they are released into the wild. This centers are of great importance for the conservation of the species, especially those that are endangered or vulnerable. The contact with animals should be the minimum to avoid humanizing them and not change their behavior so they can survive once reintroduced in nature.

Some centers also breed in captivity threatened species, such as the Hermann’s tortoise (Testudo hermanni) to try to recover wild populations introducing the offspring in nature.

Eagle flying in the Wildlife recovery center “El Valle”, Murcia. Photo taken from Murcia enclave environmental

Unfortunately, some animals are unrecoverable due to his injuries or behavior, so in the center they lived some birds of prey such as the goshawk (Accipiter gentilis) to be an example in environmental education and awareness.

If you find an injured animal, NEVER try to keep, treat or feed it: probably you’ll cause more injuries. Always call one of these centers or local authorities. They have the facilities and appropriate knowledge to treat these animals.

1. CLEAN, CLEAN AND…  MORE CLEANING

The first information I got when I entered the center was: “80% of the time of this work is to clean the animal facilities. But the remaining 20% ​​is  worth rewarding. “

The director was right. It is a job where you’ll get dirty, and if you’re a little apprehensive, it is not for you or you’ll need to get used (and believe me, you get used to almost everything , cleaning was not the hardest thing I faced). But see how it goes ahead an animal that you have taken care, is priceless.

2. THE WONDER OF WORKING IN THE MIDDLE OF NATURE

The dream of many biologists is working in direct contact with nature. These centers are usually in it, which gives the opportunity to work outdoors, away from the stress and pollution of the city. Sometimes it rains, makes a blazing sun or cold temperatures will freeze your hands and cut your skin. But the good times are terribly comforting. Many of us prefer put up with occasionally adverse weather conditions  rather than being locked in a windowless office for 8 or more hours

In my case we also had a pair of attached facilities outside the center and had to go every day strolling through the woods, with the added appeal and adrenaline (especially if you met a wild boar) to see animals and plants in their habitat.

Natural park of Montseny. Photo by Mireia Querol

The field work was completed by the laboratory and treatment room: analysis of feces, blood, muscle… to detect the presence of parasites in new animals, future reintroduced ones and dead ones: autopsies allow to have a record of possible diseases and epidemics of local fauna.

3. GIVE LIFE… BUT ALSO QUIT LIFE

In addition to maintain proper hygienic conditions, the main occupation that I had was to feed the animals. At that time there were mammals like hedgehogs, badgers or foxes which we fed with fodder and supplements such as worms.

For raptors, one of the most frequent tenants, the diet was based mainly in chicks and mice. The chicks were bought frozen, you just had to plan the thawing and leave them on their premises. In one case I had to hand feed one tawny owl (Otus scops) with a broken wing, so the contact with the animal was inevitable. And feeding a nocturnal bird of prey, althought it was a small one, is complicated task the first time!

autillo, xot, Otus scops,
Tawny Owl (Otus scops). Photo by Mario Cea

The mice instead were kept alive. By ethics and risk the animal was injured, we had to kill them with the least possible suffering before serving them as food. To learn the technique and do it properly, creates a sense of contradiction, so it’s better to focus on the animal you’re trying to save as a peregrine falcon (Falco peregrinus), a viper (Vipera Aspis), a tawny owl (Strix aluco), kestrels (Falco tinnunculus), a hawk (Accipiter gentilis)… For herbivores, such Hermann’s tortoises (Testudo hermanni), was much easier to prepare their food. And the nicest thing, to feed a baby squirrel (Sciurus vulgaris).

Nurse feeding a baby squirrel. Photo by Ezequiel Becerra

The hardest moment is where you have to euthanize an animal. Unfortunately, some animals are seriously injured and you can not do anything to save them. In other cases, if it is not priority species (such as gulls, pigeons, invasive species…) lack of resources and/or legislation euthanasia is the only solution left. First the animal anesthetized to avoid unnecessary suffering, and then euthanized with a syringe directly into the heart to make it as fast as possible. Find the heart with a stethoscope and have to check it has stopped is one of the most harrowing experiences that I had to live there.

So death is also present in these centers. Causes frustration and sadness see dying an animal you are trying to get ahead, or having to euthanize it to avoid suffering, but it is one of the difficulties it has to be faced.

4. HUMANS, THE MAIN REASON OF INCOME OF WOUNDED ANIMALS

The animals arrived to the center through forest rangers, with which you have constant communication, associations or other institutions or individuals. On occasions we moved because it was impossible to move the animal: a huge wild boar (Sus scrofa) hit by a train. The collisions are a leading cause of death of wild animals. The situation could not be more daunting: rain, the animal on the roadside in a pool of his own blood and mud. Were difficult times as we had to apply higher euthanasia doses than normal because he clung to life, besides having to ensure our own security. Finally, for all of us the suffering ended. Dirty and sad, we get on the jeep back to the center.

Fox hit by a car. Photo taken from 20 minutos

The possession of wild animals as pets causes accidents by negligence or ignorance of their owners: was the case of an eagle which it had cut its primary feathers so he could not fly when it wasn’t a harmless chick anymore. He had to undergo surgery and expect to grow new feathers and learn to fly again.

Pets themselves also causes serious injuries: for example tortoises, iguanas bitten by dogs…

The traps, poisoning and direct shots of hunters , even on protected species like raptors, is another cause of having animals in these centers. Birds also face hazards such as power lines, pylons, wind turbines, wired fences … death traps for many of them.

Dead eagle because shot pellets. Photo taken from Quo

There were few cases where the causes of admission to the center were natural or impossible to determine. In fact, I do not remember any.

5. THAT FEELING WATCHING A RECOVERED ANIMAL FLYING TO FREEDOM

The most wonderful moment is that one in which the animal is ready to return to nature. Planning how and where, taking the journey to the place, checking the surroundings (and if lucky, with the sighting of other species) the moment you open the cage. .. and you see these two kestrels that you have been feeding for months, eager to rise into the sky, you with binoculars in your hand observing them away into the vastness to become tiny black dots… and disappear. I’ve never seen more clearly a metaphor of what freedom is. That feeling, like love, can not be explained.

Maybe it is love, after all


Querol Mireia Rovira

Cover photo: Mireia Querol. Griffon vulture (Gyps fulvus) in flight over the Foz of Lumbier (Navarra, 2007).

* The photos of this post do not belong to the animal rescue center, they are used as an example of the species listed in the post

Nocturnal birds of prey: the barn owl, legends and myths

Nocturnal birds of prey have suffered since a long time ago an unfair bad reputation that has led them in some cases to be persecuted and hated. What are these superstitions? Which is their conservation state? What can you do for them? In this article you will discover owls and the barn owl, Tyto albaand the legends associated with them.

GENERAL CHARACTERISTICS OF NOCTURNAL BIRDS OF PREY

As its name suggests, most nocturnal birds of prey (owls, owls, tawny owls) have nocturnal or crepuscular habits. They are carnivorous, with beaks and claws (two toes forward and two backward) adapted to tear flesh from their prey (small mammals, birds, reptiles, large insects ).

HEARING

Owls usually have a rounded shape and apparent large head, with the face feathers forming the so-called facial disk. The facial disc serves as a dish heading sounds towards the ears. The opening of the ear is large, with a fold of skin (preaural halda), which functions as a pinna and is movable as in some mammals.

Oído de lechuza norteña (Aegolius acadicus). (Foto tomada de Jim McCormac).
Norther saw whet owl ear (Aegolius acadicus). (Photo by Jim McCormac).

The position of each ear is asymmetric in some species (one is higher than the other), so some of them -like the barn owl- can locate prey in complete darkness: an ear perceives sound before the other, so their  brain can calculate the exact place where prey is (directional hearing).

Boreal owl skull, cráneo de mochuelo boreal
Boreal owl skull (Aegolius funereus) where can be seen the asymmetric hearing openings and sclerotic eye rings. (Photo taken of Jim Williams)

EYESIGHT

Owl’s vision is highly developed. Eyes, unlike most birds, are in front position, which allows a perfect estimation of depth and three-dimensional vision. On the other hand, eyes are tubular (not spherical like ours) due to the large size of the cornea and lens, which prevents owls from moving them within their sockets. Also they have a protective bone plate around the eyes (sclerotic rings) that also impede movement. To solve this problem, they are able to turn his head 270 degrees. It can be considered that they see in black and white (they best perceive changes in light rather than colors), the pupil dilates a lot in bad light conditions (iris is hidden by dilated pupil) and they are the only birds in which the eyelid closes up to below. They also have a transparent lid” that moistens and protects the eye, called the nictitating membrane.

Visión lechuza, binocular, vista, búho, razces nocturnas
Binocular vison of a nocturnal bird of prey. Humans have a field vision of 180 degrees, 140 of them binocular). (Image by The Owl Pages)

PLUMAGE

Owls, unlike diurnal birds of prey, have a special flight feathers structure, fringed at the top surface and contours. The friction between them and the air is damped, achieving a spectacular silent flight undetectable by preys.

Pluma de lechuza común y autillo, donde se observan las barbicelas. (Foto tomada de Pedro Montoya).
Barn owl feather (Tyto alba) and european scops owl (Otus scops), (Image taken of Pedro Montoya).

THE BARN OWL

The barn owl (Tyto alba), is unmistakable: it has a very well defined and heart-shaped facial disk. The back is gray with golden spots and fine black and white dots.

DISTRIBUTION AND BEHAVIOUR

The barn owl lives all over the world (except Antarctica, north Europe and most Asia) and don’t build a nest, but lays eggs in tree holes, holes in the rock or human buildings (barns, attics, farmhouses, castles, churches ).

Why the barn owl has this negative reputation that caused their persecution in many parts of the world and in Spain? Causes are diverse, all fed by human fear:

  • They can nest in abandoned or sacred locations as churches (some with their own cemetery).
  • Nocturnal habits
  • They are sendentary, they can stay in the same hunting ground for years until food is scarce.
  • Ghostly appearance due to their colors and smooth and silent flight.
  • By their vocalizations (they have 17 different ones) like human screams and peculiar snorts. Listen to some owls making a defense vocalization in the following video:

THE BARN OWL IN THE POPULAR CULTURE. BELIEFS, SUPERSTITIONS, MYTHS AND LEGENDS

In the Iberian Peninsula was believed that owls drank the oil of the lamps in churches, leaving the Saints in the dark (when the real thieves were sacristans). By landing on lamps or touching them and pouring the oil, it was believed that owls hated light, like evil spirits. In spanish and catalan there are sayings that refer to this myth. They were hunted, killed and hanged above the doors of churches and barns to ward off fire and lightning.

The vocalizations of barn owls are also interpreted as announcements of death, and there is a belief (without basis) that if someone hear an owl for several nights (something not difficult given their sedentary habits) a person suddenly will lose life.

Tyto alba, lechuza común, lechuza de campanario
Barn owl (Tyto Alba). (Photo by Kerkuil André).

In other cultures there are also negative legends about owls: in Africa that are sent by sorcerers to kill people or evil demons announcing disasters, in the Argentine pampas that they are sisters of the devil; in Sicily, death or illness for all these reasons they have been killed and tortured.

However, they can also be a good sign (such as guardians of women who die in Australia), but the best known case is the representation of Athena, Greek goddess of wisdom. Currently still appears as a symbol of many institutions and in Greek euro coins.

Euro grecia, euro griego
Greek euro. (Resource: RTVE)

CURRENT STATUS AND THREATS

Nowadays the barn owl is in a state of decline and with an uncertain future due to changes introduced by humans in rural areas, such as changes in cultivation or use of pesticides and rodenticides, which kill their prey (mice) or indirectly birds themselves. The works and renovations of buildings where they used to nest also interfere with reproduction. They also suffer accidents due to the towers and power lines and are often hit by cars. Canary subspecies (Tyto alba gracilirostris) is disappearing due its habitat fragmentation and the low number of individuals in their populations.

Lechuza muerta
Barn owl in a barbed wire. (Photo by PacoT).

It is listed as Endangered in the Red Book of Birds of Spain and included in the National Catalogue of Endangered Species in the category “Special interest“.

WHAT CAN YOU DO FOR OWLS?

Try to find out about these magnificent birds and make them known to your immediate surrounding, banishing misconceptions, especially if you live near their nesting and feeding areas. If you own crops, try to minimize the use of pesticides: a pair of barn owls hunt in average about 2,000 mice a year, being therefore even beneficial to humans.

If you find an owl or wounded bird, you have to pick it carefully (using a towel or a jacket) to avoid hurt it or being hurt, and leave it in a dark, quiet place inside a box pierced so it can breathe. Do not feed it. Then contact a wildlife recovery centre.

REFERENCES

If you enjoyed this article, please share it on social networks to spread it. The aim of the blog, after all, is to spread science and reach as many people as possible. Feel free to share your experience with birds of prey in the comments below. ¿Do you know someone who still believe in this owl legends?

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