wildlife Archives - Page 15 of 16

20/08/201708/10/2017

Finding The Optimal Diet For Corvids

Although corvids are generally known as scavengers and omnivores, the diet of the different corvids species does vary considerably, from species to species, and over the seasons of the year. Only about 40% of the rooks’ diet for example consists of animal protein, and those being mainly worms, bugs and larvae. They usually don’t eat carrion, as their beak is not designed and able to rip animal carcasses into manageable pieces. The remaining 60% of the rooks’ diet are plant-based products like fruits, seeds and vegetables. During the winter time, carrion crows prefer seeds, berries and carrion, whilst during the summertime they do mainly live on animal protein like snails, worms, insects, small mammals and eggs.

Hatchlings And Nestlings Up To 3 Weeks

When raising hatchling corvids it is important to feed a purely insect based diet for the first two weeks of their lives. Ideally these birds should be fed on an insect mash consisting of the following ingredients:

Frozen fresh insects like crickets and wax worms
Mineral and vitamin mixture like Korvimin ZVT+Reptile (WDT)
Boiled egg yolk
Soaked NutriBird Bird Complete pellets (Versele-Laga)
Minced beef
Small amounts of feathers and fur should be added to the mash occasionally, but only when the bird is older than 2 weeks, which will help to produce pellets

Alternatively one can also create a baby food mixture (Modified recipe, original recipe by Samantha Bedford of Bedfordshire Wildlife Rescue) based on the following ingredients:

2 parts ground up (80%) chicken biscuits (Applaws Kitten Food Chicken)
1 part Hagen Tropicana Breeding Mash
1 part Heath’s Prosecto Insectivorous Soft Food
Dried ants, flies and daphnia
Korvimin ZVT+Reptile by WDT (Nutrobal for Birds by Vetark)
Bene-Bac Powder for Birds and Reptiles by PetAg (AviPro Plus by Vetark)

Nestlings Older Than 3 Weeks

When the bird turns 3 weeks, we would start reducing the amount of mash and introduce soaked cat biscuits in addition to the mash fed, which are of an ideal consistency and therefore easy to use for hand feeding. GoCat Chicken and Duck Complete pet food for adult cats (Purina) is well suited for corvids, as it provides the needed high protein contents required. It contains 20% rehydrated meat and animal derivatives, with a minimum 4% chicken and 4% duck (30.0% protein, 10.0% fat content). Tinned dog or cat foods are not a suitable diet for corvids and will most likely cause diarrhoea.

Fledglings

When the birds have fledged, a broader variety of food items will be added to the daily corvid menu, which will be provided in addition to hand feeding in a dish to encourage self feeding. Food will be supplemented with Korvimin ZVT+Reptile by WDT (Nutrobal for Birds by Vetark) to avoid a calcium deficiency. Alternatively one could also grind thoroughly cleaned empty snail shells, which make a good cheap, natural and easily digestible calcium supplement. The basic diet plan for all corvid species consists of:

Soaked cat biscuits (GoCat Chicken and Duck Complete pet food for adult cats (Purina)
Minced beef
Vegetables (fresh corn or maize, corn on the cob or peas)
Fruits (berries, grapes, apple or pear)
Scottish Rough Oatcakes
Good quality bird food seed mix enriched with peanuts, suet pellets and dried meal worms
Live meal worms (larval form of the mealworm beetle – tenebrio molitor) and wax worms (larval form of the wax moth – galleria mellonella)
Dead or frozen fresh insects like crickets, calci–worms (larval form of the black soldier fly hermetia illucens) or natural pinkies (larval forms of bottle flies)
Hazelnuts or walnuts for jays
Occasional food items in particular for crows include dead mice, day old chicks, raw pigeon eggs and cuttle fish bone

Worms and snails must not to be fed to corvids, although being part of their natural diet, as they are carriers of coccidia and worms. Although birds are being encouraged to feed themselves, assisted hand feeding needs to continue until the birds are completely weaned. Fledglings should also be moved into a suitable and spacious aviary, where they can learn to forage and are able to cache food.

01/08/201708/12/2022

Anting Behaviour Observed In Crows

Our routine aviary cleaning procedures also involve the cleaning of drinking and bathing facilities of our crows. This is usually seen with great anticipation by all our corvids. Birds in general, but in particular corvids, are very clean birds, and can’t wait to make use of a refreshing bath. We frequently add natural apple cider vinegar to bath and drinking water, which keeps the water longer fresh and has positive health properties for the birds.

The video shows carrion crow Emma taking advantage of a bath in natural apple cider vinegar, before we have been actually able to add drinking water to dilute the vinegar further. This behaviour can be seen as the equivalent to or a variation of anting, frequently observed in the wild.

Anting can take on different forms. Some birds will pick up ants in their beaks and rub them over their feathers, while others will open their wings, lie down and allow ants to penetrate their plumage. Birds seem to prefer using ants that produce formic acid. Formic acid is being used by ants as a defense mechanism.

One theory on anting is that the formic acid could act as a fungicide, bactericide and insect repellent, while others think that it is the vitamin D content in the acid that birds are interested in. However, birds sometimes use alternative anting tools, such as millipedes and fruit, and in our case apple cider vinegar. Some scientists believe that anting is used to preen feathers and helps to prevent the drying out of the plumage. Another suggestion is that anting has an intoxicating effect on birds, as some birds have been seen to shake themselves and seemingly lose control over their ability to walk.

Carrion Crow Emma Anting

30/06/201723/01/2023

The Amazing Recovery Of Carrion Crow Pan Tau

Pan Tau, a juvenile carrion crow, came to us for rehabilitation via a veterinary surgery, where the kind finder, who rescued and cared for the bird for more than a week, has brought Pan Tau to seek professional help. The veterinary surgeon actually already suggested to put Pan Tau to sleep, but the finder insisted to give him another chance. This is where we got involved and agreed to take over the care of Pan Tau.

Pan Tau has been found unconsciously on the road after being hit by a car. He suffered a severe spinal injury, which resulted in a paralysis of wings and legs. Luckily, Pan Tau didn’t suffer fractures or other internal injuries. However, the spinal injury or spinal contusion resulted in his inability to stand, sit, walk or fly. We treated him accordingly and never stopped being amazed and encouraged by his trust and determination.

Pan Tau’s Determination Was The Key To Success

Although there was no breakthrough after a fortnight, Pan Tau did show some subtle improvements, which persuaded us to continue with treatment including an intensified form of physiotherapy. About four weeks after the accident his balance problems started to improve and he was able to sit by himself on his hock joints. The spasms in his feet also started to resolve. Another four weeks later he was able to stand and started to walk and even perched the first time, still having coordination and balance problems.

After about three months of intensive care and rehabilitation Pan Tau could be moved into an outdoor aviary, where he enjoyed the new freedom, independence and interaction. Pan Tau will not be releasable, as he has got still some neurological, mainly balance issues and his flying skills are not good enough. He is meanwhile a fully integrated, well accepted and indepedent member of our residential crow family.

The recovery of Pan Tau, despite all odds and scientific predictions, is an amazing story in itself. We remain fascinated by his personality, his determination and his ever surprising ways to show us how much he is enjoying life, which is his way to say thank you for being giving this chance.

15/06/201723/01/2023

A Close Up Encounter Of Animal Awareness

This short story of carrion crow Boing Boing’s first encounter with another crow unknown to him, whist being introduced into our communal aviary, nicely illustrates what animal consciousness or awareness is about. Animal consciousness is the state of self-awareness within an animal, or of being aware of an external object or something within itself.

Carrion Crow Boing Boing

Boing Boing is a now six year old male carrion crow, who came into our care four years ago, when he started to cause behavioural problems to his previous carers. Boing Boing has been hand raised after he has been found orphaned as a youngster, also being at the time in a very poor condition. He is not releasable and a permanent resident, as he is suffering of a scissor beak, which makes it impossible for him to survive in the wild. Boing Boing would not be able to eat carrion, as his beak disorder will not allow him to tear his food into manageable pieces. We took over his care at the time carrion crows usually mature, and when they commonly show behavioural issues, in particular when held in captivity without companions, adequate housing and mental as well as physical stimulation.

Carrion Crow Chili

Chili is a young dominant male carrion crow, who has been found together with his sister Pepper after becoming orphans following the destruction of their nest during a storm. Another sibling died during this accident, but Chili and Pepper luckily survived, despite suffering of starvation, injuries and infections. Due to Chili’s personality being characterised by a strong will and determination, he grew up quickly and took on the vacant position of the territory holder. His sister Pepper is rather the opposite of Chili, having had considerable problems with her legs caused by calcium deficiencies. She is very gentle and shy, but also very observant and clever.

Animal Consciousness And Awareness

When we introduced Boing Boing into the communal aviary, Chili immediately came, which was not unexpected, to greet the new arrival. Boing Boing announced himself with a cawing display usually used by dominant birds or territory holders when arriving at the communal roost. During this display head and neck are held forward whilst neck and belly feathers are raised. Wings are usually closed and the tail is fanned out slightly. Whilst cawing, the head will be slowly lowered until the beak is touching the belly, and at the same time the nictitating membrane is drawn across the eye. Then the head will be moved up again back into the normal position, and the display begins again. Chili replied to this demonstration by immediately sleeking down his feathers to appear smaller and less aggressive, meaning that both birds have, without any aggression or even fight, just addressed and clarified their position in their crow society.

Carrion crow Boing Boing sitting on a perch in our communal aviary. — Carrion crow Boing Boing

But this was not the end of Boing Boing’s and Chili’s first encounter and communication. Both birds sat silently on the perch next to each other for more than a minute. Boing Boing was intensely looking around taking all the new information in, whilst Chili seemed unable to take his gaze of Boing Boing’s beak. Eventually Chili made his move by approaching Boing Boing and by gently and carefully examining Boing Boing’s beak by using his own. Boing Boing didn’t move, he did not even twitch. He allowed Chili to examen his beak. After another minute Chili stopped his assessment, now obviously having satisfied his curiosity, and then he eventually moved away from Boing Boing and flew off to continue with his usual business.

10/06/201723/01/2023

How To Successfully Rehabilitate A Wild Raven

Raven Zarathustra in her release aviary.

Zarathustra is an adult female raven, who we have rescued after being found unable to fly. The admission assessment showed an extensive bruise along the proximal end of radius and ulna of the left wing, but luckily no fractures have been found. We could only assume that she must have suffered some sort of impact trauma, most likely caused by a collision with a car. Otherwise Zarathustra showed no other signs of disease and was in a pristine condition.

Part of the usual treatment and rehabilitation programme is passive physiotherapy and controlled gradually increasing active exercise. Fractures, but also soft tissue injuries can cause secondary problems in birds like joint stiffness and contraction of ligaments and tendons, potentially rendering a bird permanently unable to fly and making him or her not releasable. Not unexpected, as in any sentient being, pain is an alarm bell which will dictate how extensive an injured body part will be actively used by the animal who has been inured. That also means that a bird will naturally not use the injured wing, or only to a certain degree, unless he or she is encouraged to do so. This is a well working mechanism, but to achieve best results early careful passive physiotherapy together with appropriate pain relief is often needed to avoid the complications mentioned above.

Female raven Zarathustra undergoing her admission assessment. — Raven Zarathustra

Depending on the birds compliance, personality and individual character there are basically two different ways of rehabilitating a bird by using passive and gradually increasing active physiotherapy. Unlike old fashioned rehabilitation approaches, which are still be taught at animal care courses, we do not avoid interacting with our patients. In fact, we heavily rely on a close bond based on trust, which helps us to achieve best results. The concrete treatment approach always depends on an individual assessment of the animal concerned. In rare cases it might be necessary though, to constrain the animal for the time needed to assess injuries, or to do physiotherapeutic exercises. This procedure is usually stressful, despite precautions being taken to minimise the impact on the bird.

Trust Is The Key Ingredient For A Successful Treatment

Over many years of working with corvids we have learned that in most cases a trust based relationship can be created, to allow even the physical contact needed to perform physiotherapeutic exercises. There is no risk of permanently imprinting or taming a bird, as this relationship is built out of a necessity, understanding and desire of the patient to recover and to get back to normal. This bond will be only temporary and is usually being cut by the patient at an appropriate time. The provision of suitable, specifically tailored aviary space is the most commonly used way to encourage a bird to perform active physiotherapy, meaning to encourage the bird to fly and to strengthen his or her muscles.

Zarathustra, a wild adult female raven, is a good example for this treatment approach based on trust, common sense and the targeted use of compliance to achieve the desired goal. She underwent her normal daily assessment and simple physiotherapeutic exercise performed usually twice a day, without the need for constraining the bird and causing unnecessary stress. Zarathustra did cooperate very well and was always in control of the situation. If an exercise did cause her any discomfort, or she was not content enough to proceed, she would either move away or she would make a non-verbal statement to make her intentions clear by using her powerful beak to gently nudge the offending hand away.

Zarathustra made a full recovery and has been successfully released after four weeks of treatment and rehabilitation.