Carrion crow Pepper came to us as a nestling in May 2014, together with his brother Chili after they have been found in a church yard after their nest came down following a severe storm. Both were cold and lethargic due to dehydration. Both suffered a concussion, but no fractures or other internal injuries. Only Pepper had a subluxation tendency of both of his metatarsophalangeal joints, which we subsequently had to splint. Both birds had a mildly deficient plumage, which we corrected via diet and supplements, and which changed into a prestine plumage one year later after their first complete moult.

In early autumn of 2015 we opened the soft release aviary doors for a small crow release group, Pepper and Chili included. As expected, it took about 3 days for all birds to leave eventually the release aviary. Chili and Pepper left on different days, whereas Pepper was the last bird to leave. All birds joint the wild flock of non-breeding birds nearby, but came back occasionally for treats.

To our surprise, two days later Pepper was back on site and in the aviary. He was perfectly fine without signs of a fight or injury. We kept the aviary doors open over daytime, but Pepper was not inclined to leave again. After another three days of trying we accepted Pepper's wishes and moved him into a communal aviary. Another release attempt one year later in 2016 failed again, as Pepper not even attempted to leave the release aviary we had open for several days.

Over time Pepper bonded with another unrealisable imprinted crow we named Colin. They became very close and quite boisterous during breeding season, so that we had to take both birds out of the communal aviary and had to built their own aviary. They enjoyed their own space very much and regularly attempted to breed, which clearly shows that our sanctuary environment is very much up to corvid standards.

Pepper and Chili were both physically strong and healthy birds at the time of release. Due to good care whilst being hand raised, and due to being in a mixed age single species aviary environment for a year, there was no evidence of both birds being imprinted. So why Pepper decided not to leave remains somewhat unclear, although we have found that a bird's confidence is a crucial ingredient for the bird to leave the aviary at the time of release.

We have found that in particular crows and to a far lesser degree rooks might not take on the offer of freedom at all, when they feel that they are not ready to go.  This resulted in birds staying for up to two years longer in captivity as physically needed. In other words, leaving the aviary is a conscious decision for the bird in question, and should not be forced against their will.

We know that Pepper is a dominant male bird, who behaves confidently showing typical vocalisations combined with postures such as raised head and puffed throat feathers. Despite Pepper being in captivity, he would never come to our hands or shoulders, and he would never allow us to pet him. Over time we trained him to take treats and the occasional medication directly from our hands. Both Colin, who is imprinted, and Pepper, are not afraid of us, when we do our aviary chores, but keep themselves always at a distance.¹⁾

When left at their own devices, both birds show generally relaxed postures with smooth body contours. As a sign of their generally relaxed state of mind and as a sign of comfort, both birds would preen or ant, even in human presence. Both frequently show gentle bobbing movements, made comfort clicking sounds or left small gifts in prominent places behind.²⁾. This behaviour usually changes slightly during breeding season, with both birds becoming more tense and Pepper showing a more dominant and sometimes a more aggressive behaviour.  Colin would not leave her nest, when we checked and replaced her eggs, but could become easily annoyed when our manipulations took too long. Pepper would feed Colin while she is on the nest incubating the eggs.

Another interesting observation is that Pepper understands referential gestures, which means he understands the principle of humans pointing to something, where Pepper then would follow his gaze towards the object of interest pointed out by us.^{3) 4)}. Pepper is also using head tilts to indicate curiosity or assessment.  Another sign of Peppers intelligent mind is that he often initiates and maintains a direct gaze, meaning he is looking directly into our eyes, which we see as a kind of intersubjective engagement, or two conscious minds meeting each other and sharing a reality.⁵⁾

During breeding season we observed another interesting behaviour, which has been produced by two out of the three of our residential crow pairs. Naturally, our sanctuary birds depend on us to provide them with suitable nesting material. We have obviously learned over time to find and offer suitable branches, twigs, dried leaves and moos, but sometimes we seem to get it slightly wrong. If we didn't get enough of one or the other material, or didn't provide the items on time or in the correct order, we would get a reminder. This usually would trigger that an unsuitable branch or some surplus leaves would be put directly into the entrance area of the aviary or into the bird bath next to the entrance area. This behaviour seems to indicate a very specific reminder, in particular as this is not something crows would do outside their nesting season. Also, every time it happened we checked, and they definitely did run out of nest material. This also could be interpreted in what researchers call “testing-signals” to evaluate potential partners or reinforce existing relationships.⁶⁾

Meanwhile Pepper is twelve years old, and signs of his age are beginning to show. He is starting to have problems again with his right-sided metatarsophalangeal joint, which is now demonstrating signs of a progressive osteoarthritis. Since we have noticed Pepper's issues, we modified Pepper's and Colin's aviary and provided more padded perches and resting areas.  We also provided pain relief and an anti inflammatory drug, which has improved the his situation.  However, four weeks ago Pepper's behaviour suddenly changed.

As every year Pepper and Colin did built a beautiful nest, Colin laid four eggs and Pepper took care of Colin. Half way into the breeding cycle Colin left the nest and the relationship between Colin and Pepper changed. They didn't fight, but both birds started to do their own things, almost avoiding each other. One day, when I entered the aviary, Pepper approached me directly, and to my surprise landed on my shoulder. We stood still for a while and talked, then I managed to coax him back onto a nearby perch. When I was about to leave the aviary, Pepper came immediately back to me and landed on my shoulder again. This time I understood and concluded that Pepper did this intentionally, to deliver a clear message. It became clear to me that he wanted to leave the aviary. Therefore I decided to take him temporarily with me into the bird room, where he instantly settled down and relaxed. Pepper did clearly show me his wishes, he translated those into a way for me to understand. This event clearly demonstrates the cognitive ability of corvids to communicate with other species and reflects genuine cognitive sophistication.

We continued the medication we started by putting his oral drugs onto a few mealworms, which he took from a small dish. The next day Pepper started to beg like a youngster for his medicated treats as soon as Kerstin entered the room, which he would not do when it was my turn to give him his medication.  He usually does take his treats from me without hesitation, but he would not beg.  This did surprise us, and repeated itself when we randomly changed our duties. The only logical explanation we can come up with is that Pepper was reminded of his early childhood, where Kerstin was the only person hand feeding him and his brother.⁷⁾

Pepper's behaviour clearly demonstrates the ability of crows to store and retrieve long term memories, and put those into current contexts. Their ability to expand experiences and warnings highlights the remarkable depth of their memory. When a crow encounters positive or negative experiences, they do remember the incident and its implications and the person’s face. In fact, they may remember the person’s face for a lifetime, recalling it whenever they cross paths again.^{8) 9) 10)}