Egyptian geese spread parasites and eat crops

Invasive Egyptian geese living in Germany rely heavily on agricultural crops and host a wide variety of parasites, according to a four-year study by Goethe University Frankfurt and the Senckenberg Biodiversity and Climate Research Center.

Originally native to Africa, the waterfowl were brought to Europe centuries ago as park ornaments. Today, between 11,000 and 15,500 breeding pairs inhabit Germany. Because of their ecological impact, the birds have been listed as invasive species of European Union concern since 2017.

Researchers examined the crop contents and parasite burdens of 100 birds collected during hunting operations in the Wetterau area near Nieder-Wollistadt and Dortelweil. Agricultural landscapes and waterways dominate the region, offering diverse foraging options for the expanding flocks.

Opportunistic feeding habits

Analyses showed that the birds feed primarily on grains, grasses, and corn, though they occasionally consume small invertebrates such as earthworms and bivalves. During one sampling cycle, immature strawberries were also discovered inside their crops, suggesting access to produce grown or discarded near human settlements.

Corn proved to be especially important, making up nearly half of all crop volume and almost 60 percent of total dietary weight. Researchers observed that the geese target whichever food happens to be most abundant, warning that large flocks gathered near farms could potentially cause financial harm to local growers.

Diverse parasite hosts

The examination also revealed 17 parasite varieties, seven of which were documented in European Egyptian geese for the first time. Around half of the sampled birds harbored the intestinal thorny-headed worm Polymorphus minutus, an organism acquired by eating tiny crustaceans known as copepods.

Scientists noted that these parasites could present health risks to farm poultry and native wild species. The study authors emphasized the need for continuous research throughout the entire year to evaluate how shifting weather and habitats influence what the geese consume and transmit.