Search

Pigeons, doves and crop milk

on 31st January 2007

2a.jpg3a.jpg

Pigeons and doves, belonging to the family Columbidae, are either grainvorous or frugivorous, eating seeds or fruits respectively. This does not mean that these birds eat exclusively seeds and fruits. Many also eat invertebrates, especially insects, worms and snails.

However, unlike other plant-eating birds that initially feed their chicks on soft invertebrates like insects and spiders, pigeons and doves feed theirs on a sole diet of crop milk, also called pigeon’s milk, especially during the first few days after hatching.

This crop milk is a highly nutritious surry of fluid-filled cells that slough from the lining of the crop. It is rich in fats and vitamins A and B. It is said to be richer in protein and fat than cow’s milk or even human’s milk for that matter. It consists of 12% protein. 6% fat and 1-2% minerals and amino acids, the remainder being water but no carbohydrates.

The young squab stimulates the production of crop milk by putting its bill into the buccal cavity of its parent, which in turn touches the sensitive sides of the nestling’s gape to make it open up (left: top, middle). The adult bird then regurgitates this crop milk directly into the throat of the young.

You may ask why is it that these birds do not feed their young with the same food that the adults eat? The main diet of the adult is plant materials and these are not digestible to the young during the initial stages of their development. As the young develop, their diet includes an increasing proportion of plant materials until finally they are fed the same diet as the adult.

As the chick gets ready to be fledged, they are fed more fruits and less crop milk. In the lowest image, the chick has a fruit, probably a local cherry (Muntingia calabura) in its bill.

The above images are by Chan Yoke Meng who documented the nesting ecology of the Pink-necked Green Pigeon together with Gloria Seow, a full account of which can be seen in Gloria’s blog.

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

Other posts by YC Wee

7 Responses

Leave a Reply

Your email address will not be published. Required fields are marked *

Categories
Archives

Overall visits (since 2005)

Live visitors
724
7401
Visitors Today
51619356
Total
Visitors

Clustrmaps (since 2016)