The road to Minatitlan is the free road between Colima and Manzanillo. Birding can be good anywhere along this road as it winds through thorn forest and oak forest while crossing the Sierra Madre del Sur mountain range. Two productive stops not too far outside of Colima are the roads to Agua Fria and Agua Dulce. Agua Fria is gated so if you start your day early you may want to begin birding the Agua Dulce road and stop at Agua Fria on the way back.
To get to to the Minatitlan road, go to the glorietta (roundabout) by the shopping complex that has the Soriana store and the theater. If coming from Comala, go right, passing between the two Pemex stations. After .6 miles the road comes to a stop light with a Kiosko on both corners. Go right here - the road to Minatitlan. After about six miles you will come to the bridge over the Rio Armeria, often bone dry due to its water being diverted for irrigation. Continue on for about 4 miles to the entrance to Agua Fria on the left.
Agua Fria is a "balneario" or water park, in this case taking advantage of a crystal clear stream to create a pleasant spot for picnics, wading, or partying. The surrounding woodland has produced Short-tailed Hawk, Citreoline Trogon, Gray-collared Becard, White-throated Magpie-Jay, and Orange-breasted Bunting among others. A weekday visit is recommended. Although there is no charge, consider supporting the concession stand.
The road to the tucked-away little town of Agua Dulce is just .5 miles past the turn off to Agua Fria. This dirt and cobblestone road winds through rugged agricultural land and deep forest along a small permanent stream before ending at the town. Traffic is light and there are lots of places to pull off to enjoy the abundant birdlife. Start by pulling off at the bridge and look for kingfishers along the river and Russet-crowned Motmot in the scrub. 
As the road turns right it runs between some agricultural fields where buntings abound. Watch for Painted, Varied, and Orange-breasted Buntings as well as other spectacular birds like Squirrel Cuckoo, Lineated Woodpecker, and Red-breasted Chat.
As you wind up the hill towards the village of Agua Dulce, watch for a small corrall and a road leading off to your left. There is now also an outdoor restaurant serving fried fish similar to that on the La Caja road. Walking this road may be productive for tanagers, Citreoline Trogon, Orange-fronted Parakeet, and White-throated Magpie-Jays. Fan-tailed Warbler has been found along the stream across from the corrall.