An injured bird at the municipal pond in Bolesławiec was reported to us by a reader who was walking near the body of water on Sunday. On the footbridge leading to the islet, he noticed an injured waterbird.
The black-and-white bird with a characteristic, curved bill is a male goosander. This species belongs to the duck family and feeds mainly on small fish, which it catches while diving.
Our reader's attention was drawn to the animal's left side of the head. As can be seen in the photographs, the bird has no eye, and there is an extensive wound or scar from an injury in its place.
What could have happened?
The cause of the injuries cannot be determined unambiguously from the photographs. However, there are several possible scenarios.
Mechanical injury is the most likely explanation. The eye may have been lost as a result of an attack by a predator, a fight with another bird, a collision or catching on some object.
Another possibility is a severe infection of the eye or sinuses. Some infections can lead to swelling, tissue necrosis and loss of the eye, although the appearance of the wound more closely resembles the aftermath of an old injury than an active infection.
Parasites or neoplastic lesions are much less likely.
Does the bird have a chance of functioning normally?
What can be seen in the photographs looks more like a scarred or partially healed wound than a fresh, bleeding injury. Many birds can adapt to life with one eye, as long as the other side remains functional and the animal is able to obtain food effectively. They may also retain the ability to fly. It is worth noting, however, that without one eye an animal loses the ability to accurately assess distances. Birds with one eye (remaining in the wild) have considerable problems hunting, avoiding predators and navigating the terrain.
The situation is different for birds living near humans. One such example is the male swan from the pond in Bolesławiec, which has lived without one eye for years and manages well when food is available.
Returning to the male goosander, it is worth observing its behaviour. If the goosander swims normally, reacts to its surroundings and feeds independently, there is a high probability that the injury occurred some time ago and the bird has learned to function with it.
Symptoms such as apathy, a lack of response to approaching people, problems maintaining balance or difficulty obtaining food should cause concern. In such a situation, the animal may require help from a wildlife rehabilitation centre.