Cactus Dwellers

FOR THE PAST twenty years we have been fascinated by the nesting of birds on the desert. Where birds find food, a suitable climate, and a range which is not over-crowded they are able to adapt themselves to the nesting sites available. This pastime of discovering and studying the various birds nests starts soon after the new year begins by choosing the location we are going to work. Sometimes a new site is chosen or we may return to the one of the preceding year. Trips over the area show us the last year's nests and we become familiar with the Mourning Doves have not standardized their choice of sites on the desert as they nest on the ground, in cactus, or in desert trees.

This Palmer Thrasher was raised in a nest built in the cholla blanca, the “jumping cactus.” range of birds in the country decided upon. Of course, using a location for several years gives a greater advantage.

The warm valleys of the Lower Sonoran Zone in Arizona support many desert trees but we like nest sites in cactuses and yuccas. The yuccas are members of the lily family, but typical of the desert and with long “Spanish Bayonets,” sharp and with the same “Beware” appearance as cactuses. In February we see stepped-up activity and find birds carrying nesting materials and constructing nests. The cholla cactuses which grow in height from three to ten feet are favorites for the birds. In these a person can Mrs. House Finch returned to her nest in a cholla blanca cactus to find her young with mouths open. soon learn to distinguish a nest by its location. If it is in the top it is a Cactus Wren's, near the center from top to bottom it is a Palmer's Thrasher's, and near the bottom in an open space it is a House Finch's. But there is no such standardization with the Western Mourning Doves. They build their nests on the ground, in low cactuses, high cactuses and trees.

The Cactus Wren, Arizona State Bird, is the largest of the wren Family. It is an industrious builder, constructing a shelter nest for winter as well as a brooding nest. During the period of incubation the male as a rule builds dummy nests in the vicinity of the brooding nest. This led the pioneer observers to believe they nested in colonies, which is not the case. Theirs is a covered nest generally placed at the top of the Cholla, with an opening just large enough for the bird to enter.

The nests are large pouches, spun from desert grasses, with linings of various materials. A feather lining is apparently preferred, but we often find nests lined with plant down, cotton when in the proximity of cotton fields, and where sheep have grazed the flecks of wool are gathered from thorns and barbed wire fences. The brooding nests constructed early in the nesting season are thick walled and heavily lined with warm material, while those built The brooding nest of the Cactus Wren is more lightly constructed than the shelter nest and not so heavily lined.

The House Finch likes to build a nest in the cholla blanca cactus, near the bottom and in an open space.

The Mourning Dove, a notoriously poor nest builder, does no better in a cactus and we find the same frail platform and two white eggs.

Later when it is warmer, are much thinner, with very little lining.

The Palmer's Thrasher builds an open nest in the shelter of the spiny Cholla branches, using dry twigs, generally of a thorny variety and lined with grass, also showing a seasonal difference. Those found early are constructed with thick, high walls offering needed protection from the weather, as we have found their first broods ready to leave the nests as early as March 23. As the season and heat advance the wall construction is noticeably thinner and lower.

The Common House Finch is an ardent cactus nester. We find many of their structures which they place in an open spot, low in a Cholla cactus, often in loose colonies of four or five nests. This area is within flying distance of permanent water. Their first brood in these locations are frequently ready to leave the nest by the middle of April.

The Saguaro, or Giant Cactus, grows to tree proportions and the Gila Woodpecker and Mearns's Gilded Flickers find it very satisfactory for nesting sites. By digging into the moist pulpy trunk and arms of this cactus they easily excavate a cavity. This injury is quickly sealed with a gummy coating, which hardens into scar tissue and leaves the birds a good, durable nest hole. The Mearns's Gilded Flicker is closely associated with the Giant Cactus and is seldom found elsewhere.

Since this cactus attains an age of two or three hundred years the nest sites are rather permanent contributions toward solving the bird housing problems. When the Gila Woodpecker and Mearns's Gilded Flicker have abandoned them or are driven out, they are used by the Desert Sparrow Hawk, Elf Owl, Pygmy Owl, Arkansas Kingbird or Ashthroated Flycatcher, and it has been reported they are also used by the Arizona Crested Flycatcher.

A Giant in a favorable location will show many round holes, entrances to nest cavities. The accompanying illustration shows a Giant Cactus with seven holes on one side that housed the nests of a Mearns's Gilded Flicker, Gila Woodpecker, and a Desert Sparrow Hawk at the same time.

A favorite site for the Western Red-tailed Hawk is in the arms of a Giant Cactus, situated on a hillside offering a good view of the surrounding country. One of these nests built with sticks from the Covilla, a desert bush, which are about as big around as a man's little finger was used for five consecutive years. Early in March they reconditioned it by putting on a new layer of sticks and had laid their eggs by March 25. These nests are particularly interesting to us for after following them a few years we often find them taken over by Western Horned Owls. We have never been able to observe if they are abandoned by the Red-tailed or confiscated by the Owl. Occasionally the Cactus Wrens build their nests A long tunnel leads to the nest proper where the Cactus Wren deposited her four to seven eggs. These eggs are cream colored thickly dotted with chestnut.

in a Saguaro's great arms and even the tiny Arizona Verdins seek its protection for their little ball-like nests.

The Yuccas (though not cactuses) offer nesting sites for the Arkansas Kingbird, Redtailed Hawk, Western Mocking Bird and Western Horned Owl. The Kingbird finds a convenient crotch among the stems of the Yucca flowers to place its nest. The Hawks and Owls find the tops of the Joshua Trees, over twenty feet from the ground satisfactory locations.

Looking into these nests furnishes a problem, for one does not just run up to a cactus and pull back the "foliage" or climb the trunk of the Giant Cactus with its rows of two inch spines. Several types of mirrors are necessary: the small round one such as your dentist uses helps when looking into the Cactus Wren's nest. The rear view mirror with a bracket used on the outside of cars is very serviceable around Cholla Cactuses and then the bracket threaded to fit into the end of a camera tripod which can be tied to a pole is necessary for looking into the Red-tailed Hawk's and Owl's nests. The Cholla Cactuses offer some dangers to the desert nesters, but probably a great deal more protection as few mammals and reptiles are immune from their treacherous spines. Three times we have found the mummified remains of a young rattlesnake festooned over the top of a Cholla cactus, at a Cactus Wren's nest where he had devoured the young. When we speak of birds nesting in cactus to the inexperienced it seems to them an impossibility. They picture the birds flying against the The nest of the Western Red-tailed Hawk is often built in the arms of the giant or saguaro cactus. This nest is used year after year with the addition of a new layer of sticks every spring. cactus and impaling themselves upon the spines. In our wanderings over the desert we never have found such an accident. The birds as a rule work through the spined cactus branches to their nests with marvelous dexterity. We have found their greatest danger in the cholla type of cactus is in getting a toe caught between several spines and in the struggle to get away the toe is pulled up where it is cinched and the bird dies from exposure. These deaths are comparatively rare, but we do find such cases a couple of times during each nesting season. The desire to follow the Cactus Dwellers seems to surge up in us each year when our friends begin enjoying desert picnics. We also enjoy the picnics on beautiful winter afternoons, but after a good lunch, instead of a nap in the sunshine, we must wander about a bit to see what birds are in that particular location. Soon the urge of the "hunt" overtakes us and we are out earlier in the day with just a snack that can be eaten in a hurry as we make the round of nests. By May our friends have changed to swimming parties and evening picnics, but for twenty years during May and even in the heat of June we have worked our desert locations. The Cactus blossoms are gone and even the grass is bleached and dry, and our season's work is done, for most of the birds are on the wing in family groups. Perhaps we may meet them again next year during this thrilling period.

The Gila Woodpecker favors the giant cactus for a nesting place.