There are many birds seen in the Arboretum where over 100 bird species have been recorded. Some of the most notable ones are the most common birds to be seen in the Arboretum with relative ease in different habitats as follows :

Black kite

This is a bird of prey and more so a scavenger although sometimes it hunts and captures live rodents and reptiles. It is brown not black as many people see it in the field and it has a forked tail.

Pied Crow (Corvus albus)

It is a black and white bird and more to that a scavenger which is mostly seen on the ground and sometimes hovering in the sky.

African pied wagtail (Mptacilla aguimp)

Its black and white colours are very distinctive and their tails wagging up and down when walking make it easily identified.

Common bulbul (Pycnonotus barbatus)

The common bulbul is considered one of Kenya’s most widespread birds. It its brown above, with a dark head and throat, white underparts and a very distinctive yellow under the tail coverts.

Turacos

Hartlaub’s turaco (Tauraco hartlaubi). It is a common highland turaco, dark–headed with an iridescent blue-black crest, both sides of the face marked with conspicuous white Loral spots. Bright reds on flight and a dark red bill, it is a fruit eater. Purple-crested Turaco (Tauraco porphyreolophus chlorochlamys). This is a new visitor to the Arboretum. It is common and very local in open woodland and riverine forest and sometimes may be found on scattered trees and tall euphorbias. It is a dark turaco with iridescent purple crown and shining green forehead. No white around eyes.

Other birds include the African black duck, Variable sunbird, Olive thrush, Baglafecht weaver, Speckled mouse bird, Cinnamon-chested bee-eater, Bronze manikin, White-eyed slaty flycatcher, Hadada ibis, Red-eyed dove, African goshawk, Little sparrow hawk, African harrier hawk, Bronze sunbird, Silvery-cheeked hornbill, Grey-olive greenbul, Narina trogon and African goshawk, various types of weaver birds, etc.

Some of the rare forest-dependent birds recorded include the Grey wagtail migrants from Europe and the Eurasian cuckoo and the Willow warbler from Asia. Bird ringing is regularly carried out in the Nairobi Arboretum by the Ornithology Section of the National Museums of Kenya. This involves capture of birds in mist nets, then tagging and then releasing them. This exercise, over time, has provided valuable scientific data.