Naturalist View March 2010

Naturalist View March 2010…It’s Nesting Time


Spring is here, and the raptors are nesting! We have had Red-tail Hawks, Cooper’s hawks and Great Horned owls nesting here in Saddlebrooke. Our community provides shelter and food for these hunters.

Hawks are carnivores that belong to the category of birds known as raptors -- birds of prey. They have strong, hooked beaks; their feet have three toes pointed forward and one turned back (the Great horned owl reverses one toe when catching prey so that it has two forward and two back for a better hold); and their talons, are long, curved and very sharp. Prey is killed with the long talons and swallowed whole or torn to bite-sized pieces with its sharp beaks and talons.



Until recently some people shot raptors thinking that they were competing with ranchers and farmers for things like chickens. Remember the cartoon characters Henry Hawk and Foghorn Leghorn?

These cartoons were fun but may have perpetuated the notion that hawks were after the farmer’s chickens, when in reality they were more apt to be hunting the mice and rats in the fields. Certainly they are of great benefit to us here at Saddlebrooke. Not only are they fun to watch, but they hunt pack-rats and mice.

I wish to thank all of the residents who have stopped using poison bait to control rodents and have switched to live traps. Hopefully we won’t lose any more wildlife to secondary poisoning. On a sad note, we have recently found two Red-tailed Hawks that were shot! Both were found in Saddlebrooke but were probably shot in the hills near here. If the persons responsible are found, there are severe federal consequences.

Comparisons

Based on general body shape and flight habits, hawks are classified into different groups - the most common being the Accipiters and the Buteos.

The Sharp-shinned Hawk, the Cooper’s Hawk and the Goshawk are Accipiters. They have long tails and short, rounded wings that enable them to dart through and around trees in pursuit of their principal prey, other birds. Typically, they fly low with a series of rapid wing beats followed by a brief period of sailing, then another series of wing beats.

The Buteos are the largest of the hawks. They are the broad-winged, broad-tailed soaring hawks that are more readily seen because of their habit of circling high in the air or perching in trees or on telephone poles along the road. They include the Red-tailed, the Red-shouldered, the Swainson's, the Rough-legged and the Ferruginous hawks.

The Red-tailed hawk is large bird that feeds mainly on rodents. It flies fast and has excellent vision. It can spot prey from hundreds of feet in the air. The Red-tailed is commonly seen in Saddlebrooke.

Description

The Red-tailed is one of the largest hawks, usually weighing between 2 and 4 pounds. As with most raptors, the female is nearly 1/3 larger than the male and may have a wing span of 56 inches. This species shows a great deal of individual variation in plumage.

The adult has a rufous-colored tail that may or may not have a black terminal bar. Adults are dark brown on the back and the top of their wings. The underside of the bird is usually light with a dark belly band, and a cinnamon wash on the neck and chest. Immature hawks resemble the adults, except their tail is brown with dark bars, which molts in during its second year.

The adult Red-tailed Hawk is easily identified. When it leaves its perch on slow, measured wing beats, or turns while soaring overhead, the broad, rounded tail shows a rich, russet red, hence the name. Within its range, its frequent soaring and loud voice are a good pointer.

Curious Facts:

The eyesight of a hawk is 8 times as powerful as a human's.

Like all hawks, the Red-tailed Hawk's talons are its main weapons.

85-90% of the hawks diet consists of small mammals.

The Red-tailed Hawk has hoarse and rasping 2- to 3-second scream that is most commonly heard  while soaring.

When parents leave the nest, the young utter a loud wailing "klee-uk," repeated several times
- this is a food cry.

Behavior

The Red-tailed Hawk is the most widespread and familiar member of the American Buteos (large soaring hawks). They nest in the month of March in tall trees. Like all other Buteos, it does not fly fast but soars at high altitudes using its keen eyesight to spot the slightest movement in the grass below. It is an aggressive bird and vigorously defends its territory, especially during the winter months when hunting is difficult

Habitat

The Red-tailed Hawk is usually found in grasslands or marsh-shrub habitats, but is a very adaptable bird, being equally at home in deserts and forests

Food and Hunting

The Red-tailed Hawk is a most opportunistic hunter. Its diet is varied, but there is conclusive evidence that 85 to 90 % is composed of small rodents and rabbits. Snakes, lizards and birds fill out the menu.

Breeding

Mating and nest building begin in early spring, usually in March and continue through May. This is accompanied by spectacular aerial displays by both males and females. Circling and soaring to great heights, they fold their wings and plummet to treetop level, repeating this display as much as five or six times.

Nests are located from 35 to 75 feet high in the forks of large trees. The male and female participate in the building of the nest, which is a platform constructed of sticks and twigs, lined with greenery. Both males and females assist in nest construction. Nest sites may be used from year to year, since there is strong evidence that hawks mate for life. If the old nest is wind damaged, layers of new nesting material are added each year.

The female usually lays 2 dull-white to bluish-white eggs that are marked with a variety of irregular reddish spots and splotches. Incubation takes 28-32 days and is maintained almost entirely by the female. During this period the male hunts for both of them, bringing food to her in the nest.

When hatched, the young are covered with white down. They grow slowly and require much food, which keeps both parents busy. They remain in the nest for up to 48 days. During the last 10 days or so the young, which now appear as large as the parent birds, practice flapping their wings and balancing in the wind on the edge of the nest, preparing for the days when they will launch themselves into the air.

The hawks average lifespan in the wild ranges from 13 - 20 years.

Naturalist View Feb.2010

When February arrives in Arizona I start thinking about spring and start looking and hoping for a spectacular wild flower season. I remember a few years back when, my wife, Jeanne and I drove to Kitt Peak and looked out across the desert at spectacular gold and blue fields of Mexican gold poppy, lupine and owl clover.

The spring flowering season in Arizona spans from mid February to mid June with a peak from March to late April depending on rainfall and temperatures during the growing season. In the warmest areas of the lower desert it is normally a couple of weeks earlier. The winter annuals can create an incredible display, but do so only rarely. Later-blooming species bloom more dependably, but not in the great masses of color. Winter annuals such as lupines, poppies, and owl clover create carpets of color for which the Sonoran desert is so famous. This event may occur between late February and mid April. Annuals are highly dependent on rainfall. The massive and widespread displays may occur only about once a decade, when the winter rains are both earlier and wetter than normal. A good bloom cannot be reliably predicted more than a week before it begins and lasts at peak beauty for no more than a week or two. The local papers usually report when and where the best displays can be found.

Herbaceous perennials and small shrubs such as penstemon, brittlebush, and fairy duster also require rain to bloom but are less sensitive to its timing. They are somewhat more dependable than the annuals, making a good show in about half of the years and peaking in March. These species usually grow as individuals or in small patches and do not create the large masses of color. Nevertheless they are worth looking for and are photogenic to boot.

Cacti, because they store water, are fairly independent of rain. They bloom well nearly every year though wetter years produce more flowers. The greatest diversity of spring-blooming species can be seen in April. The cactus show continues as the abundant prickly pears bloom in early May, followed by saguaros from mid May to mid June.

Mid February we begin to see nesting activity of the Great horned owls and Red tailed hawks. You may have been hearing the owls calling to their mates around 4-5 am since late December and you have probably noticed pairs of hawks circling the skies in January. Like most raptors they mate for life but split up after the young are raised (so that they are not competing for hunting territory) then they seek each other out for the next mating season. Very romantic!