Strangely enough, Bombay has more birds than meets the eye. If you care to look, you'll notice that crows, pigeons and sea gulls are not the only birds in the city. Parrots and sparrows are very common. Many migratory birds tend to make a halt on any of the green patches in the city. Herons and pelicans have been seen in the Bombay harbour. Keep watch, you may spot something to confound the experts thoroughly.
I have seen a kite sitting on the TIFR lawns. Since the building acts as a windbreak, it had some trouble getting off ground. While it was trying desperately to soar, I estimated its wingspan at about a foot-- a small bird.
Sunbirds can be seen often. These small glittering birds, most commonly a shimmering dark green or blue, are sometimes mistaken for hummingbirds because of the way they hover before flowers. There are no hummingbirds in India. If you see one of these, its a sunbird.
Flycatchers are seen in many parts of Bombay. I have sometimes seen the blue and orange variety, about the size of a sparrow. Apparently many more varieties can be seen, specially in the northern suburbs.
The pied crested cuckoo (Clamator jacobinus) is a monsoon visitor. Coloured black and white, with prominent white patches on black wings, it reaches the city three days before the first monsoon showers. Visible all over the city, it is called the chatak or Papiya in Hindi. It is listed in the IUCN red list as being of "least concern". [Wikipedia]
The intermediate egret (Egretta intermedia) is easy to see in quiet spots on the coast or near a body of water. For a month or so I saw them foraging on the lawns of TIFR, before deciding to stalk them with my camera. The easiest way to tell them from the great egret is by size: these are less than a meter tall. They tend to stalk with neck forward, unlike the great egret, which can stand in one spot much longer. These stalked through the grass and leaves, pecking at insects through a whole morning. The intermediate egret is in the "least concern" category of the IUCN red list. [Wikipedia]
The little egret (Egretta garzetta) is a common sight in winter along the coast wherever there is some peace and quiet. I've seen it on the lawns of TIFR and in Sewri. Look for the white plumage with black legs and beak. In Sewri I saw one stalking through the mud and water looking for prey. Now and then it would stop, crane its neck, and hold perfectly still for a moment. Then its long neck would dart down into the water, and it would come up with something in its beak. It is in the "least concern" category of the IUCN red list. [Wikipedia]
The black-tailed Godwit (Limosa limosa) is rarer, being in the "near threatened" category of the IUCN red list. However, fairly large numbers seem to inhabit the mudflats of Sewri.It has a very distinctive long beak, brown and buff plumage, and in flight shows white feathers on the wings with a black edging. You can see groups of Godwits at the tide line, pecking at the mud for insects. They forage and eat with their heads down. [Wikipedia]
The Indian pond heron (Ardeola grayii) is very common near ponds and the edge of the sea. A buff gray in colour, with a short neck and thick beak, its colour is transformed in flight to a flash of white. I saw this individual sitting in deep meditation by the edge of a tide pool in Sewri, watched admiringly by a common sandpiper from a further edge of the same pool. [Wikipedia]
Saurabh Rindani adds [4 Nov, 95]:
Incidentally, on my last visit to TIFR (March end this year), I was thrilled to see a pair of white-cheeked bulbuls (which I saw for the first time -- they are too rare in Ahmedabad) taking turns to go into a bush to feed babies. I could not see the nest. Unfortunately, that was when I was waiting for the TIFR bus (this was near the gate of the residential complex), and I had to leave.
Another interesting thing I encountered in Bombay was that I saw a myna near my parents' place in Santa Cruz. There was only one, which had strayed there. It was clearly a stranger and was being given a tough time by a crow. Mynas are a dime a dozen in Ahmedabad, and even TIFR. But in all these years, I hadn't seen a myna in Santa Cruz.