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.

On the morning of Christmas eve 2006, I work up late to hear the soft, gurgling coos of more than a dozen Pink-necked Green Pigeons (Treron vernans) perched along the midrib of the fronds of my two ceram palms (Rhopaloblaste ceramica) (above left). These palms, among the tallest palms/trees around the area, are favourite perches for many species of birds, from Oriental Pied Hornbills (Anthracoceros albirostris) to Long-tailed Parakeets (Psittacula longicauda) and Javan Mynas ( Acridotheres javanicus).

The Pink-necked Green Pigeons are always around towards the end and early periods of the year, pairing up and making courtship sounds and behaviour. Some birds simply pair up and perch quietly most of the time (left). Others try to slowly edge close to an opposite sex, to be accepted or rejected. If rejected the targeted bird will fly off to another perch. Other birds perch alone, either because there are not enough partners to go around or they have yet to be matched.

On this morning the air was suddenly filled with the harsh cries of a pair of Tanimbar Corellas (Cacatua goffini) that flew in to join the pigeons (top right). These corellas are larger than the pigeons and more aggressive, besides being more vocal. They were gamboling about the palms, landing on the leaflets of the fronds and chasing each other. In the process they were actively chasing off the pigeons by flying directly at one pigeon after another.

Invariable the pigeons would fly off the perch to land on another frond. This went on for some time, with the corellas shrieking loudly and flying around the palm crowns, chasing each other and frightening the pigeons. In due course most of the pigeons flew off to find a more peaceful tree elsewhere. After about five minutes the corellas flew off to anther tree leaving only a few pairs of the more tolerant pigeons alone.

This was the time when my starfruit tree (Averrhoa carambola) was fruiting and the corellas were raiding the green fruits, leaving numerous partially eaten fruits lying on the ground bleow.

Input and images by YC except Tanimbar Corella in flight by Chan Yoke Meng.

Cattail, also known as bulrush (Typha angustifolia) is an aquatic plant with 2 m long, narrow leaves that grow vertically up. The unisexual flowers are small and densely crowded along the end of an equally tall spike. The male flowers are crowded along the tip of the spike while the female flowers, appearing more compact, darker brown and distinctly cigar-like, are found below. The two types of flowers are separated by a short bare portion of the spike. The fruits are minute and covered with fluffy hairs that help them in wind dispersal.

Scarlet-backed Flowerpeckers (Dicaeum cruentatum) regularly collect the hairy fruits when they ripen. These birds can be seen perching along the spike and carefully picking at the fluff. In the process they shake off more of the fruits than they collect. This no doubt helps in the natural dispersal of the fruits (below).

The fluff is used to line the inside of their pouch-like nests. Various sunbirds also use these fluff to line their nests.

According to our bird specialist, R. Subaraj, cattails make an excellent habitat for certain birds such as bitterns, reed-warblers and rails. They also provide a good hiding place for various waterbirds.

At about 4.00 pm on 12th December 2006, K.C. Tsang sighted a small flock of the birds at the Punggol grasslands just before the rain. As can be seen in the above image, the birds were caught in the rain, and trying to dry themselves.

Sooty-headed Bulbuls (Pycnonotus aurigasteris) is native to Myanmar, South China and discontinuously through Southeast Asia to Java. The first sighting of this exotic species was reported in the early 1920s. The bird was recorded on and off, albeit rarely, throughout the remaining part of the century. A small feral population appears to have established in Tampines since 2003. Obviously the bird is breeding successfully.

According to our bird specialist R. Subaraj, “Sooty-headed Bulbuls (both gold-vented and red-vented forms) have occurred as escapees for many years now due to their popularity in the bird trade.

“In the 1970s, a feral population established itself and the species was listed on the Singapore checklist but that population apparently died out and the bulbul was subsequently removed from the list.

“There now appears to be a feral population in the Punggol-Serangoon area and a breeding record seems to have been obtained. As a result, it was been reinstated on to the Singapore checklist as a feral species in October.”

“Oriental Pied Hornbills (Anthracoceros albirostris) (above), Tanimbar Corellas (Cacatua goffini) and Red-breasted Parakeets (Psittacula alexandri) making loud squawking and screeching sounds got me to abandon my figging at Turnhouse Road in Changi last week. “The birds all seemed to have a stake in the two Heritage trees (above); the parakeet flew in and then out. Eventually the corellas settled for the smaller cavity in the Gluta malayana while the bigger hornbills claimed the bigger hollow in the Shorea gibbosa tree. “The male hornbill waited outside while his female disappeared into the Shorea cavity (above, left). After a while he flew off and brought back a red fruit, possibly jumbu bol (Syzygium malaccense) which he fed to the female when she peered out from the tree-hole (above, right). It must be quite spacious in there because the male had to dip his head right into the hollow before she reappeared. They flew off after a while. An hour later they were back again for another short visit.

“I’m wondering if these activities in the hollow of the Shorea will harm the tree. Although there are only a few short branches high up there, clumps of fresh young leaves are growing at the ends. The Gluta seems to fare better with more foliage.

“Has the courtship ended? And then will the female be sealed in?”

Angie Ng
27th November 2006

Note: Oriental Pied Hornbills are getting common on mainland Singapore. There is an earlier account on the courtship behaviour of a pair at Changi, seen in October 2006.

Input and images by Angie Ng.