This coming Friday (June 5th) is World Environment Day, with the theme for this year being ‘Time for Nature’. The focus is on the role that nature plays in providing the essential infrastructure for life on earth and human well-being. For this reason, today’s Birding From Home post is about a group of birds that play an important role in forest restoration – the Hornbills.
Hornbills in general
Hornbills are a group of medium-sized to large birds that occur in sub-Saharan Africa and southern Asia. They have huge bills that are shaped like a cow’s horn, hence the name, which make them easy to recognise.
There are between 57 and 61 species of hornbill in the world, depending on which authority you consult. About 26 species in Africa and the rest are found on the Indian sub-continent and south-east Asia. Most of Africa’s hornbills are not highly threatened, but several of the species in Asia, especially the south-east Asian islands, are under serious threat of extinction. Three are listed as Critically Endangered on the IUCN Red List of Threatened Species. The Sulu Hornbill Anthracoceros montani of the Philippines is one of the rarest birds in the world, with only about 20 breeding pairs left.
All hornbills were initially grouped in the same family (Bucerotidae), but more recently the two Ground Hornbills have been split into their own family (Bucorvidae).
Broadly speaking, there are two main groups of hornbills in Africa: those of savanna and open woodland, and those that are forest specialists.
Hornbills are generally omnivores. However, those found in savanna tend to be more carnivorous while those of the forest mainly eat fruits. About 11 of the continent’s 24 hornbills are found in forest, and it is these species that can play a big role in forest restoration.
How hornbills help forest restoration
Hornbills that live in forests are highly dependent on fruits. Some species eat them almost exclusively. Being such big birds, they swallow fruits whole. They only digest the fleshy part of the fruit and defecate or regurgitate the seed undamaged as they fly around the forest. This helps to spread the tree seedlings far and wide and keeps the forest healthy.
A recent study of two species of hornbill in India found that they can disperse seeds up to 13 km away from the tree where they got them. Another study on Trumpeter Horbills Bycanistes bucinator in South Africa estimated that they can carry seeds up to 14.5 km from the parent tree. In deforested areas, these hornbills travel long distances between separate forest patches and could help to replant trees where they had been lost.
Hornbills are not the only birds that help with the dispersal of tree seeds, but they definitely carry them much further than most other birds. As a group, they also disperse the seeds of an impressive variety of trees. An estimated 748 plant species are dispersed by hornbills in tropical forests. They are so effective at this that some people call them the “farmers of the forest”.
Ecosystem services that benefit people and wildlife
In this way, hornbills benefit all the animals and people who depend on forests. This is just one example of the many priceless ecosystem services that wild animals provide for the benefit of both nature and people.
With forest restoration being an important part of strategies to minimise the impacts of climate change, it is clearly important to conserve birds like hornbills; and the myriad of other wild animals that contribute to the health of forests. (Learn about other forests birds found in Kenya in this past blog post)
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