Karura Forest #35: What a load of (bul)bul!
The cache, a plastic bottle, is hidden at chest height under bark pieces in a hole in a small twisted tree a few metres off the south side of the Tara Path in the northern part of the forest. If you listen, you may well hear the sound of this bird, as you will throughout most of the forest.
To reach the cache location:
a) Via Gate A (Limuru Rd): after paying your entry fee and parking at the KFEET centre (S 01 14.438 E 36 49.096) head north via Junctions 12, 11, 27, 26, 30 and 37 to access the Tara Path which crosses the Ruaka River just east of Huruma Village (see here for map with trail names and Junction numbers). Follow this up and then contour east to the cache location (passing numerous caches along the way!). See GC4PD3V Karura Forest #1 for background information on the forest, including features, access, maps and useful links.
b) Via Gate C (Kiambu Rd): after paying your entry fee and parking nearby (S 01 14.395 E 36 50.643), head north down the track parallel to the road and then follow it past the Ruaka River swamp (and cache!) access track, past the East Side cache location, then over the river and onto the Tara Path. The cache location is approx 600m (10-15 minutes walk) from the bridge.
The yellow-whiskered greenbul or bulbul (Eurillas or Andopadus l. latirostris, 18cm) is a solitary species of songbird in the Pycnonotidae family. It is the commonest highland greenbul. The adult is a dull olive green with distinctive bright yellow whiskers down the 
sides of the throat and a reddish-brown tail.
In Kenya it is very common within its range of highland forest (strips), riparian undergrowth and wooded gardens from 700-3,000m. It also occurs in much of sub-Saharan Africa as far south as Uganda.
It calls and sings throughout the day a dull ramble of chirrup, chup and chop notes, with occasional bursts of higher pitched chattering (listen here. Its protracted rambling and chattering is a dominant feature of many wooded areas (like Karura). Its diet includes fruits, berries, molluscs, woodlice, spiders, frogs, and geckos.
When breeding the males gather and sing at lek sites. Females then gather at the leks and choose male. 1-4 eggs are laid and incubated by female only for 12–14 days. Outside of leks, both care for the young.