Birds are ingenious nest builders, using a variety of natural and artificial materials to create their homes. However, not all materials are equally suitable or safe for birds and their offspring.
A new study by researchers from Bangor University and Poznań University of Life Sciences has revealed how man-made materials in nests can have both positive and negative effects on birds.
The diversity and prevalence of man-made materials in nests
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The researchers used a large database of nest materials used by 176 bird species around the world, and analyzed the types and amounts of man-made materials they incorporated into their nests, as per Phys.org.
They found that birds use a wide range of anthropogenic materials, such as plastic, metal, paper, fabric, rubber, glass and cigarette butts.
The prevalence of man-made materials in nests varied among different regions and habitats, with urban and coastal areas having more than rural and inland areas.
The researchers also found that some bird groups, such as gulls, terns, crows and pigeons, were more likely to use man-made materials than others, such as woodpeckers, owls and hummingbirds.
They suggested that birds may use man-made materials for various reasons, such as availability, durability, flexibility, insulation, camouflage or decoration.
However, they also warned that some of these materials may pose risks to birds and their nests.
The risks and benefits of man-made materials in nests
Man-made materials in nests can have both positive and negative impacts on birds and their offspring. On the one hand, some materials may provide benefits, such as protection from parasites, predators or weather, as per Birds Caribbean.
For example, cigarette butts may repel ectoparasites that suck blood from nestlings, while plastic films may help keep the nest warm and dry.
On the other hand, some materials may cause harm, such as entanglement, ingestion or overheating. For example, baler twine or fishing nets may trap or strangle adult or young birds, while plastic pieces or metal fragments may be swallowed by mistake or puncture internal organs.
Moreover, some materials may reflect sunlight or retain heat, causing the nest to overheat and dehydrate the nestlings.
The researchers recommended that people should reduce the amount of plastic and other man-made materials that they discard into the environment, as these may end up in bird nests.
They also suggested that people should provide safe and natural materials for birds to use instead, such as twigs, leaves, straw or pet fur (if untreated with chemicals).
The study shows that man-made materials in nests are widespread and diverse among bird species around the world, and that they can have both risks and benefits for birds and their offspring.
The need for more research to understand how different species of birds and different types of materials affect nest success and survival has been reiterated.
They also urged people to be more responsible and mindful of their waste disposal and recycling practices.
