Cormorants prove Charles Darwin’s hypothesis on plants

This video from Taiwan says about itself:

The Cormorants (1 of 4)

9 March 2010

The [great] cormorant is a large water bird with black plumage. It has a wingspan of about 100 centimeters. From the Ussuri River region of Siberia and the northern-east region of China they fly to spend about five months in Kinmen; they do not embark on their return journey to the breeding grounds until April the following year.

The cormorant is equipped with webbed feet, a strong bill, easily wet-able feathers and a special flexible pouch on its throat, making the bird an efficient catcher of fish. Highly gregarious, the cormorants like to feed and roost in large numbers. They also fly in line formations. Every year the entertaining antics and sheer number of these birds attract many visitors, both domestic and abroad, to Kinmen.

From Biology Letters:

Great cormorants reveal overlooked secondary dispersal of plants and invertebrates by piscivorous waterbirds

Casper H. A. van Leeuwen, Ádám Lovas-Kiss, Maria Ovegård, Andy J. Green

4 October 2017


In wetland ecosystems, birds and fish are important dispersal vectors for plants and invertebrates, but the consequences of their interactions as vectors are unknown. Darwin suggested that piscivorous birds carry out secondary dispersal of seeds and invertebrates via predation on fish.

We tested this hypothesis in the great cormorant (Phalacrocorax carbo L.). Cormorants regurgitate pellets daily, which we collected at seven European locations and examined for intact propagules. One-third of pellets contained at least one intact plant seed, with seeds from 16 families covering a broad range of freshwater, marine and terrestrial habitats.

Of 21 plant species, only two have an endozoochory dispersal syndrome, compared with five for water and eight for unassisted dispersal syndromes. One-fifth of the pellets contained at least one intact propagule of aquatic invertebrates from seven taxa. Secondary dispersal by piscivorous birds may be vital to maintain connectivity in meta-populations and between river catchments, and in the movement of plants and invertebrates in response to climate change. Secondary dispersal pathways associated with complex food webs must be studied in detail if we are to understand species movements in a changing world.

10 thoughts on “Cormorants prove Charles Darwin’s hypothesis on plants

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