Ecological Sanctuary Wildlife Refuge (Finca Ecológica, tel./fax 506/2645-5869, www.ecologicalsanctuary.com [1], 7 a.m.–6 p.m. daily, $10 adults, $8 students, $5 children), on the same road as the Butterfly Garden [2], has six signed trails through the 48-hectare property, which has waterfalls.
You have an excellent chance of seeing coatimundis, sloths, agoutis, porcupines, and white-faced monkeys, as well as butterflies and birds. It offers a twilight tour at 5:30 p.m. ($25 pp including transfers).
Sendero Tranquilo (Quiet Path Reserve, tel. 506/2645-5010, 7 a.m.–3 p.m. daily) has a three-hour guided tour beginning at the Hotel Sapo Dorado.
New in 2010, Ficus Trails (Hotel Fonda Vela, tel. 506/2645-6474, ficustrailmonteverde [at] gmail [dot] com) has bird-watching tours at 6 a.m. and night walks ay 5:30 p.m.
Meanwhile, the Hidden Valley Nature Trail (tel. 506/2645-5156, 7:30 a.m.–4 p.m. daily) has two-hour night walks at 5:30 p.m.
Links:
[1] http://www.ecologicalsanctuary.com
[2] http://www.moon.com/destinations/costa-rica/guanacaste-and-the-northwest/monteverde-and-santa-elena/sights/wildlife-exhibits