Moapa Valley National Wildlife Refuge
Pacific Southwest Region
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Calendar of Events

Wildlife Calendar of Events

Whiteriver Springfish


This calendar is meant to provide a general guide to seasonal events on Moapa Valley National Wildlife Refuge.


The palm trees and warm water springs afford thermal protection for many species of birds during the winter months. In particular, great horned owls roost in holes and openings among the matted and tangled palm tree skirts.


White-crowned sparrows are present in large numbers, primarily in the upland areas. Belted kingfishers swoop above the warm water streams, hunting for food. Male California quail become vocal in the early spring as nesting begins.


Although Moapa dace spawn year round, spawning activity reaches its peak during the spring. Turkey vultures return to the Moapa Valley area and throughout the summer evenings, roost in the in the palm trees in the Plummer Unit. The desert tortoise, a federally listed threatened species, emerges from its winter burrows. Weather is generally pleasant, but occasionally quite windy.


Spring wild flowers begin to bloom, with the number and variety highly dependent upon the amount of rain received earlier in the year. House finches nest in the palm tree skirts. Neotropical migratory birds, such as yellow-rumped and yellow warblers, pass through the Pedersen Unit as they head north to their nesting areas, making use of the native riparian vegetation along the stream banks.


Movement of young-of-the-year Moapa dace from refuge streams to the main Muddy River reaches its peak. Abert's towhee, a species tied to the Lower Colorado River system and its tributaries, begins nesting. Broods of California quail are common, as this resident species nests two or three times during the year. Barn owls nest in rock crevices in Battleship Wash. Bats begin to appear at night as the air temperature warms up and insects start to flourish.


Bullfrogs can be heard croaking loudly from the spring heads and stream banks, especially towards dusk. Red-tailed hawks that nest elsewhere in the Moapa Valley teach their young to hunt in the uplands between the Plummer and Pedersen Units. Bare snags make convenient perches and look-out posts. Wild flowers remain in bloom until month's end.


Temperatures begin to soar, regularly reaching triple digits during the day for extended periods or time. Tortoises return to their burrows, but other reptiles, particularly the western whiptail and zebra-tailed lizard, can be observed. Palms flower and cast a heavy perfume after dark. A flashlight beam among the fronds reflects the tiny glints of hundreds of moths seeking nectar from the palm flowers.


Summer monsoons can occur during this time, causing minor wash-outs and moderate flooding as the level of the Muddy River rises. Cottontails and black-tailed jackrabbits frequent the upland areas. Late summer broods of California quail can be seen. Mourning doves are heard calling from spring through fall and they make use of the sunflowers going to seed in the Pedersen Unit.


Temperatures moderate, generally by month's end. The number of Moapa dace on the refuge reaches a low as spawning activity decreases. Migratory birds pass through the refuge on their way south for the winter. Tortoises may reappear for a brief feeding period prior to winter hibernation.


Turkey vultures leave the Moapa Valley area. Ring-tailed cats are active after dark. Temperatures decline and weather conditions become generally pleasant. National Wildlife Refuge Week is celebrated during the month.


American kestrels and Northern flickers are present and readily visible all year. Dark-eyed juncos arrive to spend the winter in a warmer climate.


Say's and black phoebes occur year round. The former is common near buildings and other artificial structures, while the latter is partial to the pools and streams.

Last updated: June 23, 2009