There are anywhere from 88 to 146 species of birds in Macau, depending which source you consult. I haven't found anywhere near that many, so I won't get in the middle of that argument.
On most of my trips I didn't have too much time for bird watching in Macau, but have managed to check a few off my list. Even if you don't plan on designating any time to bird watching, you should be able to pick up a few too. Here are some I have that are worth posting.
Spotted Dove. One that is both easy to find and identify is the Spotted Dove. These can be found in many city parks and sometimes even in more populated areas. It is a grey dove and has a black band with white spots around its neck.
Oriental Magpie-Robin. I've only been able to identify this one on the coast of Coloane between the main square and the fishing pier. I may have seen some at the lake in Taipa, but I wasn't able to get a good enough look or picture to be certain. If I had a better camera, I may have been able to see some from the pedestrian walkway at the Rotunda do Istmo.
In two of the pictures I have posted here, you can see both the male and female (along with a Eurasian Tree Sparrow) when you view the larger photos. The male is on the left.
Eurasian Tree Sparrow - One of the surprises here for me is the sparrows. I live in an area where "small brown bird" narrows it down to about 140 possibilities, so when I started taking pictures I completely ignored the sparrows. Then later when I had time to research which birds there are here in Macau, I found out the Eurasian Tree Sparrow is the only sparrow they have. The pictures here were taken in Coloane, and the larger pictures are the same as some of the Oriental Magpie Robins above.
Last time in Coloane I took a lot of pictures along the coast. I was hoping to get a heron, egret or bittern but then found out they have nine of them, with some being very similar. The pictures I did get were too far away to identify them. The two on the right were taken from the pier at Ponte Cais de Coloane.
I am guessing that you would have to go to one of the more secluded parks or coasts if you want to get more than 10 birds here, but I will post more when I find out.
Avibase - lists 146 species, using Clements version 2015 taxonomy.
Macau Biodiversity - lists 106 species.
Wikipedia - says there are 88 species, and it can only be updated by anyone in the world, so you know it can't be wrong.