Will the tangerine make it onto the Easter card?

Easter has taken over many elements of pre-Christian spring holidays with the symbolism of rebirth of life. It also accommodates chicks, mainly chickens, but ducklings and warthogs can also appear. Today, among the farmed poultry, there are also species that were not in the traditional Polish countryside and are unlikely to find their way onto Christmas cards – guinea fowl, turkeys or muscovy ducks.

New species of ducks have also recently appeared in the aquatic avifauna of Poland. The subfamily Anatinae, or ducks, is divided into several tribes, including the Tadornini, which until recently was represented in our country by the russet(Tadorna ferruginea) and the ohara(Tadorna tadorna). In Europe, most ducks belong to the Anatini tribe. Recently, however, another kazarka – Alopochen aegyptiaca, known in Polish as goosefoot or Egyptian kazarka – has been added to the list of national avifauna maintained by the Faunistic Commission of the Polish Zoological Society. According to current law, it is included in the category of “Invasive alien species posing a threat to the Union subject to rapid eradication” (Journal of Laws 2022, item 2649). Its chicks are unlikely to count on joining the Easter symbols. The Tadornini also include the muskrat, but its presence is not considered worth noting by ornithologists, as it is a breeding animal. For that, representatives of several other species of kazarks are usually escapees from ornamental bird breeding.

An ornamental bird from the same tribe is the Carolina(Aix sponsa). As the name might suggest, it is native to North America, although its natural range extends beyond the state of Carolina. The species is not restricted to breeding and is sometimes seen in the wild throughout Poland, but as far as is known, it does not currently breed in our country other than in captivity. Nonetheless, courtship of Carolina males towards females of other duck species found in the parks has been repeatedly observed. In western Europe, pairs of this species are already breeding in the wild. Probably it is only a matter of time when this will happen in Poland as well.

Such is the case with another species of ornamental duck – the mandarin(Aix galericulata). It originated in the Far East, and its males are feathered just as magnificently (or perhaps even more so) than the diamondbacks. It is worth mentioning that the aforementioned muskmelon was also originally kept in Europe as an ornamental species, but since it is visually much more modest than the mandarin or carolina, but much more abundant in meat, there was a change in the nature of breeding.

In the list of avifauna of Poland, the mandarin has the same status as the Egyptian goose – a secondary natural species, but from a legal point of view its status is different. It is not currently considered invasive. Among ornithologists, it arouses rather benevolent interest. In general, among birdwatchers, aversion to non-native species seems to be lower than among other groups of biologists. This may be due to the high mobility of this group of animals, and individuals have appeared outside their original range of occurrence since time immemorial. This posed no threat to native wildlife, and the bird often returned to its proper migration route or habitat.

It is also related to the ornithological culture (subculture?) of collecting observations. True enthusiasts are able to travel several hundred kilometers to see with their own eyes a pelican or a Delawar gull, which sat for several days at the Rashinsky Ponds. See and note on your personal list. So, when new bird species themselves appear nearby, it makes it easier.

Finally, there is a continuum between professional ornithologists and amateurs who enjoy observing and photographing birds, but are not always aware of the dangers of their presence. An invasive bird species is more likely to find defenders than an invasive cyanobacteria species. Hence the controversy surrounding the listing for elimination of not only the Egyptian goose, but also the Canada barnacle, which has been observed in Poland for decades.

Mandarin is an alien species for now, but not an invasive one. Like the carolinella, it is found mainly in urban parks. In the Warsaw Baths these species do not stand out so much, since you can even find peacocks there. Except that while the Carolina’s in the wild are still spoken of as escaped breeders, it is in the Baths since 2001. Mandarins are already forming an independent population. They spend their entire lives outside of breeding and literally its full cycle, starting from the egg stage. The breeding population of mandarins grew regularly and the Baths became too small for them. Soon adult specimens could be found in more Warsaw parks with ponds, as well as in Vistula riparian forests. However, for several or even a dozen years they would return to the motherlode to overwinter and nest. This may be related to the fact that the mandarin is a hollow tree, and few parks have enough old hollow trees. In the second decade of the 21st century. However, even this has changed and some individuals have already hatched outside the Baths.

Most of Warsaw’s mandarins are ringed with plastic tags with large letters that are easy to read without having to grab the bird. This makes it possible to track the location habits of individuals. This is done by Warsaw’s Tridactylus ringing team. A dozen years after the population was introduced in the Baths, it seemed that its growth had slowed down to about a hundred pairs. The late 2022 avifauna list thus counts the mandarin among the species that have not exceeded the limiting number of one hundred breeding pairs. Meanwhile, a systematic count done in February 2023, conducted when the birds were concentrated on the few unfrozen reservoirs, yielded: 274 males and 164 females.

It is Warsaw’s mandarin population, being quite numerous and stable for consecutive years, that determines the breeding status of this species. However, it is not the only one. Breeding has already been observed, among others. In Radzyń Podlaski, Toruń, Gogolin, various places near Warsaw (Pruszków, Raszyn), Pępów near Warsaw. Gostyn, Zywiec and Brzeg. The latter population seemed the most promising in terms of consolidation, but at some point the end of its development was observed. This happens when there are at most a few breeding pairs.

Warsaw mandarins not only circulate all over the city today, but they even happen to fly to Finland. So it should come as no surprise that they are seen not only in parks anymore, but also in much wilder places. Then control of their numbers is difficult, and the creation of new breeding sites can go unnoticed for a long time. Tridactylus researchers are appealing to report sightings of mandarins with chicks to: https://forms.gle/Qid45vQDnvhDqFjB7. At some point, it may turn out that predictions about the non-invasiveness of this species were too optimistic. Admittedly, there seems to be little overlap between the mandarin’s ecological niche and that of native ducks – it is a forest species that likes water, but feeds on acorns, for example.

So for now, the tangerine is not a cause of serious concern for environmentalists, but instead arouses widespread sympathy. In some parks it has already become a bit more faded, but it’s still common to see people taking photos at it. It probably won’t dethrone the mallard as the archetypal Polish wild duck, but it has a chance to enter popular culture. Maybe in a while it will also appear in symbolism related to Easter.