Anyone who has ever seen a large fold (Otis Tarda) in the wild will probably not forget it so quickly. The males weigh up to 16 kilograms and are up to one meter high. Large folds are the heaviest flying birds in the world. In spring, the roosters offer a special show for the only half as big hens: they put their wings, open their throat bag and turn into a dancing white badminth popcorn on two legs.
But the great bustards can do much more: the big birds, which are often plagued by parasites and worms in the intestines, can heal themselves. As a study now shows, they are actively looking for two plants with active ingredients that kill pathogens. So, you are engaged in self-medication.
"Large raps seek two weeds that are also used by people in traditional medicine," explains Koauter Azucena Gonzalez-Coloma, researcher at the Institute of Agricultural Sciences in Madrid. The research team collected 623 excrement of female and male large folds, including 178 during the mating season in April. Under the microscope, it counted the amount of recognizable remains of stems, leaves and flowers of 90 plant species, which are known to be on the menu of the bans. Two species are eaten more frequently by the large folds than would be expected on the basis of their occurrence: gossip poppy (Papaver Rhoeas) and Wegerich -leaves Natterkopf (Echium Plantagineum). The animals selected the two plants, especially in the mating season in April, with male ate more than females. "In theory, both genders could benefit from great fans if they are looking for medicinal plants during the mating season when sexually transmitted diseases are common," explains Azucena Gonzalez-Coloma. "Males also use to appear healthier, stronger and more attractive for females."
To test whether the plants are effective against pathogens, the group isolated water- and fat-soluble compounds from both species and examined them by mass spectrometry. The researchers focused on lipids, volatile essential oils and alkaloids, which are produced by many plants to ward off herbivores. They then tested whether they could keep the three most common parasites of birds at bay: the protozoan Trichomonas gallinae, the parasitic worm Meloidogyne javanica and the fungus Aspergillus niger. The results show that extracts from both plants highly effectively inhibit and kill protozoa and nematodes in vitro, while the viper's head plant is also actively active against fungi.
In an earlier study, researchers were already able to show that great bustards are increasingly eating oil beetles, which are among the most poisonous insects in Europe. The beetles produce the toxin cantharidin, which is also active against parasites. The great bustards tolerate them very well in smaller quantities. But the oil beetles may have another effect: cantharidin is also a main component of the Spanish fly, a potency agent that is made from crushed oil beetles.
Large dummies breed on the grassland from Western Europe and Northwest Africa to Central and East Asia. About 70 percent of global population live on the Iberian Peninsula. In Germany, large dummies were almost extinct shortly before the turn of the millennium and are on the red list of endangered species. There are currently around 300 birds.
