Introduction
This blog post is aimed to provide some useful information regarding the potential need for the management of interspecies interactions between different corvid species in captivity. We are frequently being asked, mostly by rehabbers and rescue centres, if and how certain corvid species can be kept together in an aviary environment. This question often becomes of interest due to a reoccurring problem in wildlife rescue and rehabilitation – the lack of available aviary space.
To shed some light onto this topic, one has to consider two different main scenarios. If and how different corvid species can and should be kept together depends on the set goal to be achieved, as there are different considerations to be made. The two main scenarios are rescue, rehabilitation and release opposed to long-term care in a sanctuary like environment. We will discuss and examen both scenarios in this blogpost.
General Thoughts
Generally, the success of keeping any number of birds together depends on various factors, including the age range of birds concerned, the individual personalities, the size of the enclosure and the availability of food, hiding places and perches. Providing multiple feeding stations, hiding spots and other environmental enrichments can help to mitigate potential conflicts.
It is important to monitor the behaviour of the inhabitants very closely, as one should be prepared to separate them if signs of aggression or stress become apparent. This of course means that enough aviary space should be set aside to do so, to be prepared for the not unlikely event that an intervention may become required.
Introducing different corvid species can be challenging, as some corvid species are known for their territorial and sometimes aggressive behaviour. In the wild, these birds do compete for resources and nesting sites, which is a behaviour that will also lead to conflicts in captivity. However, the good news is that corvid behaviour in captivity can differ from corvid behaviour in the wild, which means that the often aggressive and territorial behaviour is less prevalent in captivity, which is most likely due to the lack of competition and survival pressure.
Corvid behaviour also varies throughout the year, with the level of aggression being at the peak point during breeding season, and at the lowest level in autumn after the main breeding season and main annual moult.
It is also important to look into species specific behaviour of the bird species concerned. As mentioned before, the most important trait to consider is territorial behaviour, which is in particular evident in carrion and hooded crows, ravens, jays and magpies. Jackdaws and rooks are gregarious birds and are used to live in larger groups. Therefore, these birds are usually less problematic when it comes to mixing them with other bird species or when kept in larger groups.
All sentient beings including corvids have their own personalities, which is a trait that will greatly impact on their behaviour. Juvenile and mature birds will also have their own acquired experiences. Learned behaviour, meaning knowledge taught by parents, siblings or other conspecifics, will also impact on the way a bird will behave and interact. This explains why young and unexperienced birds are likely more forgiving and adaptable when it comes to social interspecies interactions.
It will also be useful to learn to read and understand corvid vocalisations and their correspondent postures, when observing and analysing corvid behaviour and interactions. Hidden cameras might be of help, as the behaviour of birds will change in the presence of humans, and may not be a true representation of the actual situation in an aviary.
General Husbandry Considerations
When attempting to keep different birds and different species together in captivity, one has to consider several factors to promote positive interactions. So, what does the management of interspecies interactions in captivity involve?
The most important factor is space. One has to provide a large and well designed aviary with plenty of space allowing the inhabitants to move around, and to get out of each other’s way, if required. Corvids are intelligent and active birds, and crowding will easily lead to stress and aggression.
Another important factor to consider is enrichment. Corvids need to be mentally stimulated, which can be done by offering a variety of toys, perches and natural objects to manipulate. Corvids are known for their problem-solving abilities, so engaging activities can help to prevent boredom and will reduce the likelihood of potential conflicts.
Appropriate food is also crucial. One has to ensure an ample, healthy and varied food supply, which will subsequently reduce food competition. Corvids have diverse diets, including seeds, fruits, insects and small vertebrates. Providing different food options and varying feeding sites can help to prevent competition for resources.
When birds are kept in a sanctuary environment, the availability of multiple nesting sites can be essential to prevent territorial disputes. Rooks and jackdaws typically build nests in trees, so providing platforms or suitable structures for nesting will be beneficial. Jackdaws may also consider adequate nest boxes or other hidden places.
It is essential and self explanatory that the birds in our care have to be regularly monitored for signs of stress, aggression or health issues. If issues should arise, one has to be prepared to separate the birds concerned temporarily or even permanently, or by making adequate adjustments to the enclosure to remedy the observed problem. This is similarly a strict requirement for birds kept in longterm care, as established communities and their interactions may change with birds maturing or bonding, or birds leaving the community due to illness, death or other reasons.
New birds have to be introduced gradually and under supervised conditions. One has to ensure that there is enough space for the birds to establish their territories or private space without feeling threatened. It is often helpful when new birds are introduced to a resident community, that they are kept temporarily in an aviary which is separate but in immediate proximity of the resident aviary. This allows both, residents and the new bird to get to know each other in a save and controlled environment, before the new bird gets introduced into the communal aviary.
Last but not least, one should group birds according certain species specific factors. While some corvid species are often found together in the wild, individual birds may have different personalities, which will impact on the outcome. Regardless of the kind of scenario, there is always the need for monitoring of bird interactions to ensure that all birds do get along well.
Corvid Aviary Design And Enrichment
Caring For Temporarily And Permanently Disabled Birds
How To Care For Visually Impaired Birds
Rescue, Rehabilitation and Release
Birds being earmarked for release should be grouped differently, compared to birds which are kept long-term or permanently. Juvenile corvids will benefit from a group release, and are usually best soft released. An exception are adult birds, who can be released back into their native territory, assuming it is safe to do so. However, this should only be done if these birds are not being kept in captivity for longer than 14 days.
Hand raised corvids need to go into an outdoor aviary when they become of fledgling age, which is also the time when the weaning process starts. This process is usually done in an outdoor soft release aviary, where these birds whilst still being hand fed will also gradually learn how to forage by themselves.
Every species is usually being kept in their own specifies specific aviary. However, juvenile carrion crows and rooks can be an exception. Both species are more often being kept together than apart, which is sometimes happening rather by accident due to difficulties in identifying the correct species. They usually get on well and can also be soft released together, assuming that the release aviary is located near an unoccupied crow territory. Ideally, juvenile crows should be released into a non-breeding flock of crows, and rooks into a flock of rooks. However, as this is not always possible, the soft release of juvenile crows can also be done safely near a flock of rooks or a rookery. We have frequently observed that these youngsters are staying with a flock of rooks until they feel confident enough to move on.
Juvenile jackdaws are also being kept and weaned in their future release aviaries. We always aim to mix our release groups, regardless of the species, with older releasable or occasionally with unreleasable birds of the same species, whereas the latter birds have to be obviously removed from the release group prior to the release date.
The added benefit of grouping juvenile birds with mature or adult birds is that these birds often act as foster parents, or at least as teachers and role models, which is crucial when it comes to the acquisition of communication, social and survival skills in a captive environment. The soft release of jackdaws and rooks can be done near existing rookeries or jackdaw nesting sites, as these two species are not territorial, and aggressive behaviour towards each other is rather rare.
We have observed quite frequently that juvenile jackdaws start to bond very early in life. It seems that these bonds may continue as friendships, but they can also develop into true partnerships when these birds become sexually mature. For this reason we will always at least endeavour to keep or release bonded birds together, even if this may delay the release for one of the two bonded birds.
In our experience, jackdaws, carrion crows, hooded crows and rooks are usually the most frequently admitted birds into the care of bird rescues. Magpies and jays are less commonly seen, whilst ravens are rather rarely admitted. This also means that magpies and jays are not commonly admitted in large numbers, which implies that rather rarely a single species release group can be created, which is self explanatory when only a single animal is being present.
Juvenile magpies and jays can usually be grouped together, or being put together with juvenile jackdaws, if there is no other option. This is not ideal but far better than keeping a juvenile bird without any company at all. A major drawback is that this kind of mixed juvenile group will usually not be able to benefit from the addition of adult birds, as they are very unlikely to tolerate each other. Soft release for these two species should only be done into an unoccupied jay or magpie territory.
We don’t have any experience with choughs. Juvenile ravens have to be kept generally separate from other corvid species, as they cannot be safely mixed and need to be soft released into an unoccupied raven territory.
When Can I Release My Rescued Corvid Fledgling?
How And When To Release Crows, Rooks And Jackdaws
Longterm Care and Sanctuary
Although, many of the general husbandry and rescue and rehabilitation considerations do also apply for long term patients or in a sanctuary, there are some unique situations to consider. As we know, wild corvids behave differently in captivity as they would do in the wild. Another important point is that any kind of behaviour is possible to change over time and will be different for juvenile, sexually mature or senior birds.
We often see that disabilities amongst group members are well tolerated and may even result in supportive or altruistic behaviour between birds. This type of behaviour may also cross species boundaries. In a longterm care environment friendships may develop between young and old birds, but also between birds of different species, as often seen between rooks and crows.
Past experiences in the wild may lead to situations, where certain birds will not live peacefully together in one aviary. However, the impressive adaptability of corvids leads more often to situations, where birds get on well in one aviary, when introduced slowly and cautiously to each other. We have magpies and crows as well as magpies and jackdaws, who live happily and peacefully together, despite the mischief magpies often like to cause.
Regardless of the species or a specific combination of species living in one aviary together, there is always one potential risk to consider. A seemingly peaceful situation can change without apparent reason, and sometimes without an advanced notice being given. Therefore it is always important to continuously monitor relationships and behaviour.
In this context, there is one rule every bird keeper knows about. There is no such thing like an aviary which is too big. The biggest affordable aviary seems always too small after birds have been introduced to live in them. The bigger the aviary the lesser the chance that aggressive behaviour will develop, as birds will have a better chance to get out of each others way. This also means that preventive measures will also be more likely to be helpful, such as multiple roosting place at desirable height levels, multiple feeding stations and plenty of areas to hide and shelter.
Conclusion
It is impossible to give a general recommendation when confronted with the question of which birds or which bird species can be accommodated with each other. Many factors need to be taken in consideration, which we have tried to highlight in this blogpost. The personality of the birds concerned, their age and their past experiences are always important factors to consider.
Continuous monitoring is crucial, regardless whether these birds are kept in groups until their release or in a sanctuary like setting. CCTV monitoring might also be recommendable, as bird behaviour will change when the birds concerned feel save and unobserved. Working setups may fall apart when the internal situation changes, be it that new birds are introduced, residents pass away or maturity changes. Occasionally, but rather rarely, no apparent reason for the change of interactions can be established.
Please always consult with experts in avian behaviour and welfare, and consider ethical implications before attempting to house birds together in captivity. Keep in mind that each bird is a unique sentient being and has got its own personality, which means that there is no guarantee of peaceful coexistence even with ever so careful planning.