Brood parasites are an incredibly interesting group of birds. Instead of going to the trouble of building their own nests and raising their own young, they out-source these functions to other birds. They will lay their eggs in the nests of other breeding birds and allow them to raise their young on their behalf. They achieve this through a number of adaptations. Some species mimic the colour and shape of the host’s egg. Others have chicks with structures in their mouths which hyper stimulate the parents to feed them. The adult or chick parasite will also often kill the hosts’s chicks or remove the eggs in the nest, thus ensuring that the parasite survives. However hosts are not completely helpless to this attack, hosts have co-evolved behaviours such as abandoning a nest if it is parasitised. However some hosts are capable of raising both their own young and a parasite, without any visible cost.

Here we present 25 of best photographs of brood parasites, enjoy! If you would like to share your photographs with us, you can upload them to the Facebook page with species, location and photographer as the caption. We will announce next week’s theme this coming Sunday.

A female Asian Koel photographed in Bangalore, India. These birds commonly parasitise crows (Paneendra BA)

The square-tailed Drongo-cuckoo of south east Asia parasitises babblers mainly, evicting the host’s eggs and young (Soumitra Ghosh)

In India the Jacobin Cuckoo is believed to bring the monsoons, this is due to their arrival shortly before the rains begin (Vinayak Yardi)

Common Hawk cuckoos parasitise babblers and laughingthrushes, as a result the fledglings call is very similar to that of a babbler (Paneendra BA)

The Shiny Cowbird of South America is a generalist brood parasite, they have been recorded parasitising 240 different species (Raymond De Jesús Asencio)

A female rufous morph Plaintive Cuckoo photographed in West Bengal, India (Subham Chowdhury)

A rufous morph of the female Sunda Cuckoo. These cuckoos are only found on south east Asian islands, this one was photographed in Indonesia (Ananth Ramasamy)

The Jacobin Cuckoo is found in India and sub-Saharan Africa. They parasitise various species of babblers across their range as well as bulbuls and fiscals in southern Africa (Dr. S. Alagu Ganesh)

Female Brown-headed Cowbirds can lay up to 40 eggs in a season, damaging and removing the hosts eggs as she does (Jola Charlton)

The Indian Cuckoo of India and south-east Asia parasitises drongos and shrikes (Mohit Ghatak)

This Wood Duck is raising two of her own chicks as well as a Hooded Merganser chick (Teri Franzen)

A Jungle Babbler feeds a Jacobin Cuckoo fledgling (Shaurya Shashwat Shukla)

Black-billed Cuckoos are capable of building their own nests and raising young but they also occasionally lay in the nests of other birds (Owen Deutsch)

Shiny Cowbird chicks do not mimic their host’s chicks but nonetheless their host provisions just as much for them as for their own chicks (Mann Niyati)

Common Hawk-cuckoos are typically found in wooded areas, foraging in the tree tops (Radhakrishnan Sadasivam)

A newly fledged Brown-headed Cowbird calls for its parents (Jola Charlton)

A female Grey-bellied Cuckoo. These cuckoos usually parasitise Common Tailorbirds, the tailorbirds will abandon a parasitised clutch 20% of the time (Vishal Monakar)

Male Pin-tailed Whydahs aggressively protect their territory, chasing away any other birds (Leslie Reagan)

The colour of the Plaintive Cuckoos eggs depend on which host they use (Asutosh Pal)

In India the Banded Bay Cuckoo parasitises the Common Iora (Panthera Tigris)

An Asian Koel photographed at Hebbal Lake, India by Ravishankar P

Several Chestnut-winged Cuckoos may be raised out of a single host’s nest, this would certainly place an additional burden on these parents (Subham Chowdhury)

There are often massive size differences between parasitises and their hosts, such as this Common Cuckoo being fed by a Meadow Pipit in Ireland (Nigel Moore)

A Common Hawk Cuckoo photographed in Sultanpur National Park, India (Vishal Monakar)

On the third or fourth day after hatching, the Indian cuckoo chick pushes any other eggs and chicks out of the nest (Subham Chowdhury)

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Edited by Christie Craig, Campaign Manager