Monday, April 17, 2017

Easter walk at Saguaro National Park West



It was dry and hot and dusty. Of the wildflowers that the rainy (or here, not so rainy) winter had produced, only dry stalks and seed pods remained. Chollas and prickly pair were blooming, but I've seen better.


Insects were scarce. A bee fly with the ominous genus name Anthrax found the moisture and salt of my hand irresistible.


Foothills Palo Verdes, in beautiful bloom all over Picture Rocks, hardly showed any flowers here. But Ironwood trees were loaded with bursting buds.

There are few Mesquite Trees in the park and their flowers were past their prime. Still, they were the best source for beetles that I could find.

Megalostomis subfasciata

Coleothorpa axillaris
 Clytrin Leaf Beetles were flying around the fresh leaves, maybe searching spots to lay eggs.


Some mesquite catkins were covered in huge aggregations of mating Lycids. Often there are 2 species involved, but this time all I could find were Lucaina marginata , no L. discoidalis.

Lucaina marginata


They shared the catkins with many tiny Dermestid, Melyrid beetles and tiny Perdita Bees whose color is so close to that of the Mesquite flowers that it may take a second look to find them.


With its bee-like flight (the dark elytra stay folded over the body) Acmaeodera griffithi  could be overlooked by the beetle collector. Because I was trying to photograph solitary bees, I inadvertently focused on the Buprestid.


 While manipulating the Mesquite flowers to photograph the Perdita Bee, 2 tiny beetles landed on my hand. They are both  Dasytinae in the family Melyridae genus Trichochrous, the smaller one likely to be T. ferrugineus. (Thnks to Doug Yanega for getting this information from Adriean Mayor)

After only a quarter mile along the dusty road, our dogs were quite ready to go home to a drink and a bath in the tub. So this was a very short 'Osterspaziergang' but I could not completely let go of that lovely tradition.


Tuesday, April 11, 2017

As thick as thieves - a bee and a moth

The sky islands of Arizona are treasure islands for naturalists. When the desert wildflowers wilt in the per-summer heat of April and May, in these mountain ranges spring is only beginning. One of my favorite mountains is Mount Graham in eastern Arizona. On its highest elevations, it has beautiful mixed conifer areas and mountain meadows.

Mertensia macdougalii.
 in early summer, a herbaceousl plant in the family Borraginaceae covers acres of these meadows: Mertensia macdougalii. The flowers are set in swirls typical for this family. They are blue when fresh but change color to purple and pink when they age - probably due to ph changes in the aging flowers. They remind me very much of  Pulmonaria, an early spring herald of European forests.
Studying those flowers (looking for bugs on them) I soon noticed little injuries on the upper part most of the drooping flowers. The culprits were obvious too: bees were chewing through the side of the flower's throat to get to the nectar, instead of laboriously crawling into the flower. Easier on the bees, but of course this way, the flowers were probably left unpollinated. The bees that I observed were all of one species in the genus Colletes.


Colletes sp. bee chewing into the side of the flower to get to the nectar
Many Colletes are specialists, foraging for pollen on only one group of plants (Wilson and Messinger Carril). Even though my Mnt. Graham species is not identified and Mertensia is not mentioned in the bee-plant pairings of the book by Wilson and Merringer Carril, I may have stumbled on another such pair, or I just happened upon a group of bees (they are non-social but often nest in aggregations) that had found a good easy nectar source and stuck to it for the time being for reasons of efficiency (constancy principle).

middle: Colletes bee. right: damaged flower; left: moth
But I may have observed a clue that points to a long established relationship, which in this case is based on thievery: After trying to photograph the thieving bees for a while and thus establishing a search image for them, I realized that I was repeatedly looking not at a bee, but at a moth that was using the bee-created access to the nectar source.  Interstingly, the moth (Caloreas apocynoglossa) was always sitting head down while the bees would sit head-up. However, the moths' wing pattern 'took that into account': a dark hind-end  gave the impression of the dark head of the bee, even including antennae, and  a light patch imitated the  reflection on the bee's wings.

Moth Caloreas apocynoglossa
Two  interpretations are possible:
The bees may be armed with a painful sting - at least in comparison with a helpless moth. Predators would avoid bees and moths. So this would be direct Batesian mimicry.
But solitary bees are not usually heavily defended and many birds feed on them.

Another possibility is that the moth gains some protection from its head-down orientation: Flycatchers tend to grab their prey by head and thorax, in this case the pretend-bee-thorax - so the moth may be able to escape from the misdirected attack with minor hind-wing injuries (same idea as in hairstreaks).

But: If the relationship between bee and moth is old and established enough to have resulted in adaptive changes in behavior and pattern of the moth, it may be save to assume that the relationship of this Colletes species and Mertensia macdougalii is even older and that the bees are specialists. Too bad for the plant then, that these bees are specialized thieves!

Quoted: Thee Bees in your Backyard by JS Wilson, OM Carril, Priceton University Press 2016 

Thursday, March 16, 2017

Animals and their habitat: Harris Antelope Squirrel



 Cacti of the lower desert are important to the Harris Antelope Squirrels. They feed on the fruit of Barrel Cacti that are available all year round, ad generally stuff their big cheeks with anything from seeds to insects to even carrion. They are so dainty that they are able to jump into and hide in the most thorny Jumping Chollas. My dogs, and probably most hunting coyotes can only watch in deep frustration as the squirrel chitters only inches from their noses in relative safety. Besides coyotes, bobcats and hawks they have snakes to worry about. I have seen the little guys actively and aggressively take a stance against anything rattlesnake-related, even attacking and biting my snake stick that only smells of snakes. At this time (Feb. March) the squirrels raise their pups in underground (under cactus) burrows. All summer long, the day-active critters will brave the heat - one adaptation is their unusually high body temperature, also their little umbrella-tail and the habit of spread-eagling in shady places to dissipate heat to the cooler ground. During cold periods they seem to stay in their burrows, but during the last mild winter, a few were usually out and about.They are true denizens of the Sonoran Desert.

Animal Habitat: Cattleranch for Dung Beetles

Photo collage of my watercolor Longhorn Ranch and a digitally created inset of Canthon imitator rolling a dung ball.

Animals in their habitat: For some few animals human activity improved the environment. Cattle ranches must be paradise for many dung beetles, even in areas where historically no big grazing herds occurred. Of course it's not quite that simple: http://arizonabeetlesbugsbirdsandmore.blogspot.com/2017/02/dung-beetles-important-for-environment.html

Wednesday, March 15, 2017

Animals in their Habitat: Mountain Lion



Animals in their habitat: Mountain Lions in the Tucson Mountains. With the exception of humans, the mountain lion has the largest range of any large terrestrial mammal in the Western Hemisphere. They are found from Canada to Argentina. They are also able to utilize the low desert as well as the higher elevations of the Catalina Mountains and the territories of individuals are huge. Although they may snack on prey a...s small as mice, their main target in the Tucson Mountains are Javelinas and mostly Mule Deer. A female lion with two grown kittens pretty regularly shows up at a water feature in the backyard of a friend who lives around Gates Pass (SE Tucson Mountains). Sadly, one was killed on Picture Rocks Road some years ago - that's only a couple of miles from our house, but I've never seen tracks on our property. While I often see mountain lion footage of trail cameras at places where I do field work in AZ and Sonora Mexico, I've only seen one during the day in the wild. So the model for my painting was the female at the Phoenix Zoo - and if she was out here, she'd probably prefer a more seclude resting spot, maybe above my head in an old Mesquite Tree .. but hey, it's my painting ...

Tuesday, March 14, 2017

Animals in their habitat: Salt River Horses


Animals in their Habitat: Salt River Horses. This is a difficult topic. There is a community of horse lovers here who love this herd passionately and in a way defensively. Federal agencies have made weak attempts to remove them. When you observe the animals enjoying their free, rather secure live, splashing through the year-round running river, fighting for mates, forming bachelor groups and harems, raising foals, and all this trustingly in viewing distance of photographers and other admirers, you are apt to agree that they are a rare treasure.But any ecologist sees a growing herd of feral, not wild, horses that propagate unchecked by any meaningful predation in a very delicate desert environment. It seems difficult to find common ground. Even attempts to control birth-rates by chemical sterilization are vehemently decried by the human friends of the horses. The river so far is the saving grace - the members of the growing herd look well-fed and healthy and do not seem to stray too far into the real desert. I have not seen any impact studies concerning river banks or nitrate loads ...

Sunday, March 12, 2017

Animals and their habitat: Sphinx Moths and Sacred Datura

Watercolor and photo collage by M. Brummermann
The Moon Flower or Sacred Datura opens its flowers in the late evening. During the night, the main pollinators, Manduca spp. and other big Sphinx Moths, visit. In the morning there are still white-faced bees and other little insects crawling into the wilting flowers, but they are mostly too small to be effective pollinators.
The throat of Datura flowers is extraordinarily deep. When completely unrolled, the proboscis of Manduca rustica is long enough for the moth to hover over the flower and reach the nectar. Still, most moths land and crawl laboriously into the depth. They stay surprisingly long wiggling among anthers and stigma, and when they emerge, they head directly for another one of those white funnels. It is assumed that chemicals in the nectar may be slightly addictive and keep the moths faithful - thus assuring that precious pollen reaches its goal and does not get wasted. Datura (like many plants) is a known chemical powerhouse that produces potent Alkaloids. These may protect the plant tissue from many herbivores, but not from the caterpillars of several Manduca species who seem immune. So the pollinating moths can lay their eggs right on their favorite plant to produce a new generation for this symbiotic relationship.

Wednesday, March 8, 2017

Animals in their Habitat: Regal Horned Lizard


When photos of this lizard are posted on social media sites, the predictable comments usually are that people used to 'always' see them in the past, but not anymore. Is this true, or is this anecdotal perception just that?  On our property west of the Tucson Mountains I do see them occasionally and I'm not sure that I see fewer than 15 years ago when we moved here.
Of course they are very secretive and tend to bury themselves under loose sand whenever it is either too cool or to hot - after all they are ectotherm reptiles and need to regulate their body temps by appropriate behavior. They also depend mostly on certain ants for their diet, and these, too, are limited in their activity by the ambient temperature - meaning that extremely hot summers drive these harvester ants deeper under ground to live on their stored food. Extended droughts like the current one probably eventually diminish their numbers. So even in areas like our property, where the ants are save from insecticides and their food source (weeds) is not destroyed by herbicides or artificial ground cover, desert harvester ant populations may have been shrinking over the lat 10 years and with them the number of  Regal Horned Lizards. My (also anecdotal) observations of the Greater Short-horned Lizard in the mountains seem to suggest the those are still faring better, as are grassland populations in Cochise County. It seems however that in areas where Harvester Ant colonies are under attack by introduced Fire Ants (Texas, but not Arizona) the effect on the local horned lizard species is quite negative and the numbers are in alarming decline.

The range of the Regal Horned Lizard in Arizona is within Arizona Upland Sonoran Desertscrub, Chihuahuan Desertscrub, and Semidesert Grassland communities. It inhabits valleys, rocky bajadas, and low foothills. It is usually encountered in relatively level areas with low shrubs, and open, sunny patches. 

Tuesday, March 7, 2017

Animals in their Habitat: Foothills Kestrel


Animals and their habitat: Sometimes I take liberties when I paint: In the background of this watercolor from 1992 are the Catalina Mountains as seen from Tucson. But the Kestrel I had seen close to the Mule Mountains in Cochise County, and I liked his perch on the old Yucca stalk. Tucsonans will realize: those Spanish Bayonets do not grow in the southern foothills of the Catalinas (there are some on the north side, in the grassland towards Oracle though) Having lived here now for over 20 years, I would never again falsify a landscape like that. The Kestrel, however, would not care too much. The little falcons make their territories in grasslands, agricultural areas and in the saguaro desert, wherever there is open space around perches to hunt and nesting cavities to raise their offspring. We had a pair in our backyard for years, in an old woodpecker nesting cavity in a saguaro. They took a great toll on our lizard population which is the main menue the small male serves for the female and the chicks while he is the sole provider. Whne the larger female took to the wing again, she also served sparrows and finches.

Monday, March 6, 2017

Animals in their Habitat: Arizona Cardinals


Animals in their habitat: For some birds, their habitat requirements seem very variable. The Northern Cardinal seems to be fine where he has access to big, oily seeds, brush for nesting and some water. Still, the species' distribution puzzles a lot of human 'snowbirds'. They come from the Northeast to Arizona and find their statebird already established in their winterdigs. Did he migrate, too? No. He is a breeding resident. Was he introduced by transplanted humans who felt l...onely for their pretty red bird? I often hear that idea, sometimes vigorously defended and supported by the remark that Arizona 'really' is the territory of the 'Desert Cardinal', the pyrrholoxia. Not so. If you look at the distribution map of the Northern Cardinal you see that the bird indeed mostly lives in eastern Canada and US areas: from Maine to Texas and in the provinces of Ontario, Quebec, New Brunswick and Nova Scotia. The distribution maps of many birding books end at the souther US border. But in the south its distribution covers Mexico to the Isthmus of Tehuantepec, northern Guatemala, and northern Belize. An allopatric population is found on the Pacific slope of Mexico from Jalisco to Oaxaca; the Arizona population seemlessly extends from the north Mexican distribution. Most likely, the long north south extension of the Rockies in North America and northern Ice Ages are the reason for the peculiar distribution pattern of the 'Northern' Cardinal.

Sunday, March 5, 2017

Animals and their habitat: Bighorn Sheep in the Catalina Mountains


Animals in their habitat: Bighorn Sheep in the Catalina Mountains. When I came to Tucson in the early nineties, there were still occasional sightings of Bighorn Sheep mainly on Pushridge. Massive developments like SaddleBrook soon encroached on their area and the growing influx of hikers everywhere caused more disturbance than the sheep could take. A huge forest fire took the brush cover of the mountainside, and eventually predation as well as livestock diseases killed of the last sheep. Now, a few years ago, the forest service and game and fish (?) began an ambitious reintroduction program, releasing several truck loads of sheep over a couple of years. At first, the animals did not seem to thrive. They dispersed into unexpected areas and mountain lions killed several of them. In reaction to that predation, a number of mountain lions were hunted down, which caused a public outcry. Many in Tucsonans believed that the whole release program had been done not to bring back an established resident of the mountains, but just an attraction for trophy hunters. But I think the Bighorn population is stabilizing by now, lambs are born, young bucks still stray all the way to the Tucson Mountains and the remaining many mountain lions are probably very happy. To depict the situation, I moved a Bighorn Ram from an old painting digitally into a landscape painting of Pima Canyon on the south side of the Catalinas. While the result is artistically somewhat lacking - the landscape is overwhelmingly busy - I think this digital collage fits the situation very well, showing the introduced, wandering ram just a little too low on the mountain in the upper part of the Saguaro zone.

Saturday, March 4, 2017

Animals in their Habitat: Roadrunner


Roadrunners are one of the icons of the deserts Southwest. They are most often depicted running through open spaces of sun-bleached sand with maybe some cactus, or, cornier, an even more bleached cow skull in the background.
But our huge raptorial cuckoo-birds would not really like that cliché landscape too much. While they are tough enough and very adaptable and often run rather than fly, they still appreciate the low trees of the thornbush chaparral just as much or even more than the wide open desert.
Their nasal wouw-wouw-wouw calls are most often heard from the height of an ironwood or mesquite tree, and later I see our resident bird up there all fluffed up, turning exposed patches of his black skin towards the morning sun to absorb the warmth. I know he is perfectly able to regulate his bodytemperature by autonomous means (shivering, panting) - much better than for example the tiny hummingbird - but he seems to prefer those primitive behavioral ways.
To me, that makes him seem even more like some ancient saurian velociraptor that his sharp profile and strong running legs remind me of. Fast, fierce and insatiable and smart. Even the tiniest, blind nestlings can swallow whole lizards that the parents provide. Adults catch everything that moves, from tarantulas to House Finches to rattlesnakes. One was filmed while catching hummingbirds at a feeder. Roadrunners are probably the greatest  menace in the young lives of baby quail.  When our cat got out last summer, he came racing back with a Roadrunner in angry pursuit.
And yet - I'm delighted each time I catch a glimpse of a speedy runner or hear their fast, clacking ratchet noises in our backyard.

Friday, March 3, 2017

Animals in their Habitat: Crossidius sp. Longhorn Beetles


Animals in their habitat: for many beetles all the habitat they rely on seems to be a single plant species. They are so faithful to their hostplants that they show up on the flowers as adults, may it be to feed on pollen, nectar or the petals themselves or to meet their mating partners. The female then lays her eggs so the larvae can feed on the stems or roots of the plant. Next year, there will then be a new generation of beetles just in time for the flowers of the plant. For the sake of exchange of genetic material, I hope the beetles at least cruize the whole local population of their plants. The example here is the longhorn beetle Crossidius coralinus on Burrow Weed (Isocoma sp.?). Beetles of this genus frequent similar asteraceae all over the western US.

Thursday, March 2, 2017

Animals in their habitat: Desert Sparrows


Animals in their habitat: Black-throated Sparrows are character birds of our SW desert. All during spring their metallic song can be heard around our house in the bajada of the Tucson Mountains, but I've also found a nest in the grasslands around Cochise Stronghold on a friend's property. True to style, even that nest was hidden in a cholla cactus. But one of the five eggs in it was bigger and whiter than the other four. A cow bird had smuggled in a little parasitic guest. Th...e nest was very well protected with spiny jumping cholla branches, but my friend, being an entomologist in search of dung beetles, was armed with very long forceps. So he removed the cow bird egg. I was ambiguous about this interference, but he did the math: minus one cowbird means plus 4 sparrows, because the early hatching CB chick would have pushed the sparrow eggs out of the nest.

Wednesday, March 1, 2017

Animals in their habitat: Blister Beetles on Spring Wildflowers



 Finally! The first wildflowers and the first seasonal insects are gracing the Arizona deserts. After a relatively wet winter, poppies are popping up (ugh, sorry!) under Creosotes and around saguaros. We don't see great fields of them yet, but it's early yet. While I've never found specific pollinators on those periodic spring blooms, there are beetles that feed on pollen as well as petals of lupines, scorpion weed and poppies: several species of blister beetles, most of them in the genus Lytta. They are not the much maligned threat to life stock that some of their relatives (genus Epicauta) have become thanks to industrial hay harvesting methods. Our horses usually don't feed on poppies after all. So just enjoy those shiny little jewels! Read more about their biology in another blog chapter

Tuesday, February 28, 2017

Animals in their habitat: Burrowing Owls


Animals in their habitat: 'Burrowing Owls'. These little long-legged owls are fun to watch and don't seem to mind posing for photos and sketches. They like to take over burrows of rodents or just irrigation pipes, so they can be found in the Avra Valley fields where Pima Cotton is grown (hence the uninspired background). But they are versatile and according to literature once lived in all open spaces of the Americas (not in the tundra, though, I'd guess). They are day active b...ut do most of their hunting at dawn and dusk. They perch and swoop or just jump and run after insects, lizards and small rodents, occasionally birds. Supposedly they bring cattle dung to their nest to attract dung beetles. But I know dung beetles: they like it fresh. So I doubt that interpretation of the behavior. Another behavior seems easier to understand: from inside their burrow, incubating females often make hissing and rattling noises very similar to that of a rattle snake. Rattlers also sleep in burrows. So the imitation seems like a good sound-based Batesian mimicry that might keep a badger or coyote from getting too inquisitory.

Monday, February 27, 2017

Animals in their habitat: Gamble's Quail


Gamble's Quail Family. This species lives in the creosote and Saguaro areas of the Sonoran Desert. We have Mearn's Quail in the south eastern canyons and Scaled Quail in the grasslands further east. February is a little early for chicks, but at last weekend's art show, prints and note cards of this image sold out very quickly. So humans are eagerly waiting for spring, The male quail are also getting all territorial and sit on their perches calling 'ChiCAgo!' for hours. During most of the year, quail live very socially in coveys - probably related groups of siblings from those large clutches. Quail mothers lay 10 to 18 eggs in a protected hollow under dense vegetation or in a suitable flower pot. Not much nesting material is used. The hen does not incubate before she is completely done, and at one egg per day, this takes a while. Dangers lurk: snakes, Gila monsters, Roadrunners, Ravens, Coyotes, all love to gobble up a whole clutch. But if it works out, all chicks hatch at the same time. They are extremely precocious, fully feathered and able to follow their parents after only a couple of hours. The group does not return to the nest. Both parents are vigilant guardians, and the kids stay together instinctively. The chicks not only grow amazingly fast, they can also fly long before they are fully grown. The breeding season is long: groups of chicks can be seen from late March to late August.

 Like many desert-dwelling species, Gambel’s Quail populations undergo a “boom-and-bust” cycle. A year with ample winter-spring rainfall that generates lots of green vegetation will yield larger clutches and an abundance of chicks. Dry winters mean less food and lower productivity. So this year, we are expecting huge rows of chicks to follow their parents around!

Thursday, February 23, 2017

Animals in their Habitat: Elegant Trogons

'Habitat' includes of course the geologic base (soil and profile), the resulting plant society, climate and geographic location. But the animal neighbors are as important. They are part of the food chain as prey or predator and, usually most importantly, compete for the same resources or provide them, like food and nesting cavities. In this painting after my very first observation of Elegant Trogons in Madera Canyon (1994), I posed them and their neighbors in a thicket of Sycamore branches, Ferns and Columbine flowers. So I considerably shrunk the distance between canopy and forest floor in my imaginary world.


I think back then, Trogons, who reach the northernmost point of their distribution in SE Arizona, only migrated north for the breeding season. Trogons are primarily occupants of tropical forests, but as omnivores, they are somewhat adaptable. They glean the brush for insects and they love the berries of the Madrone tree, but they do not refuse those of introduced Pyracantha shrubs. In spring, the pair raises 2 to 4 chicks in a tree cavity, and Sycamores seem to provide the most desirable ones. Nowadays Elegant Trogons can be seen year round in SE Arizona's canyons and riparian areas.

Monday, February 20, 2017

Animals in their Habitat: Coatimundis in Sycamore Canyon


A couple of weeks ago, I was lucky enough to watch a single Coati foraging under the bird feeders of Madera Canyon Lodge. That reminded me of a quite dreamlike experience from my very early days in Arizona. I was camping in Chiricahua National Monument with a group of friends. I woke up early and peaked out of my tent.. The young bright white sycamore trees were too thin to block the rays of the raising sun. While I was drowsily squinting, the trunks seemed to sway and move. But as soon as my eyes adjusted, I recognized that the moving things were actually the straight-upright tails of a gang of coatimundis. They hung around for a while, chattering and sniffing noisily under rocks and branches that they seemed to move with their little hands.
    
White-nosed Coatis, Nasua narica, are related to Racoons. Our Arizona coatis are the northernmost ambassadors of a genus that is widespread in central and south America. They are day-active omnivores with a taste for insects, lizards, roots, fruits, nuts and eggs. They are very fond of fruit, especially manzanita berries. Normally, they weigh from 10 to 25 pounds, but the ones at Madera Canyon look like they are quite a bit heavier.
Coatis mate in early spring. A litter of 4 to 6 young is born after a gestation period of about 11 weeks, usually in a den in a wooded canyon. Coatis usually stick together in groups of one half to two dozens, but lately a group of 40 was observed in Ramsey Canyon in the Huachucas. Although they seem to like woodland and creeks, they also sometimes appear in the backyards of Oro Valley and Tucson.


Sunday, February 19, 2017

Animals in their habitat: Acorn Woodpeckers in Madera Canyon


 Acorn Woodpeckers in Madera Canyon. The creek was running underground at the time, as it does during longer and longer periods each year now. When water is a limiting factor, artificial water sources become a big draw for wildlife.
Acorn Woodpeckers don't just look like clowns. As the only social woodpecker species (that I am aware of) they are given to a lot of very entertaining antics from the human point of view. And they are smart. I'm sure these two were discussing the idiot who had closed the valve so tightly
The old little drinking fountain at the Lodge fell victim to the parking lot extensions years ago. The dated Tucson-insider title was 'CAP' Water?' An engineer from Tucson Water bought the painting

Saturday, February 18, 2017

Desert Animals in their habitat: Backyard Hummingbirds


Costa's Hummers stay year round in our backyard and the males fiercly defend their territories, often in form of a particular feeder and pearch nearby. February is already mating time and nest-building time for the females. The male accompanies his flight display with a long, piercing whistle. In our backyard, Aloes introduced from South Africa are blooming. While they are mainly ignored by local insects, Hummingbirds, Orioles (and Honey Bees) are less fussy and enjoy the early nectar board.

 Anna's hummers are also in their nuptial best right now. Gorget and forehead are shimmering in metallic colors from purple to orange and green. depending on the light refraction.  Much of their mating song is produced while sitting on the highest point of a Mesquite tree. Anna's only lately became year-round residents of Arizona. Garden flowers, feeders and decorative water features enabled them to do so - one of the species that benefited from the transformation of pristine desert into suburbia.

Friday, February 17, 2017

Desert Animals in their habitat: Urban Doves


 Mourning Doves are so adaptable. They breed on top of sun exposed cacti in the pristine desert, but I also had a pair in the tiny patio area of my very first Tucson apartment. They raised their 2 chicks in a flower pot and afterwards started right over - up to 5 times a year. I called the painting originally ' Keeping an eye on the alien'. At the time my I was on a J -Visa and and frequent questioning by border patrol agents was still upsetting to me. But when I entered the painting in a show, it was rejected. Later it won an award in a different setting. Go figure. I had changed the title, but that may not have been the reason.
As an afterthought: Today, but not in the early nineties when I painted this, our local doves, Mourning and White-winged, really have to compete with alien invaders. The Eurasian Collared Doves are pushing them out of several prime nesting sites in our backyard as we speak.

Thursday, February 16, 2017

Desert animals in their habitat: The Owls of Sabino Canyon




To me, this is also a painting of wildlife in its habitat. If you can't see it, close your eyes and listen. There: the hooting call of Great Horned Owls. I have never hiked the area at dusk without hearing them calling to each other. In fact, a Native American friend who was often with me felt their presence so keenly that they made him uncomfortable (I did talk him out of it). Why is it that owl...s have such a bad reputation in many traditional cultures? When I was a kid in Germany, my mother thought that owls might have been drawn to windows that were illuminated at night and in the old times that often happened when someone lay sick or dying. So they were thought of as harbingers of death. Anyway - I'm glad we moved away from those superstitions and can enjoy our owl sightings now. Not all old traditions are to be cherished.

Wednesday, February 15, 2017

Painting of desert animals in their habitat: Racoons

 'At Night at Sabino Creek'. Often I just find the left-over shells of crayfish in the morning, but lots of five-fingered prints tell the story. The clear, cool water shows the gold-brown color of tannins from decaying oak leaves: this creek originates high in the Catalina mountains and can tell of snow melt and towering Ponderosa Pines, rare Arizona Cypress, Live oaks  and Aligator Juniper, and finally Saguaro Cactus and lush Cottonwoods. 

Paintings of Desert Animals in their habitat: Jack Rabbit

In an effort to brighten up social Media with art postings, I will regularly post some of my watercolor paintings here and on my Facebook page.  Hopefully they'll all have some appeal to the naturalists among us as well 


We ( Jack Rabbit and I) live in the Sonoran Desert. It's not bare like the Sahara, but not usually covered in grass, either. Except after really good summer monsoon storms. A carpet of little Cheat Grass plants covers the creosote flats. But the life cycle is short and soon they are producing awfully sticky seeds.  By then the grass itself is bleached and golden until the wind blows away every trace of it. The painting was mainly about this: the short golden grass in the sun. But the Jack rabbit was there and made a great center of interest for viewers who are less intrigued by temporary Cheat Grass lawns.

Friday, February 10, 2017

Santa Rita Mountains, February 2017

Yesterday morning I finished my 'Coyote Prowls' and then headed south for the Santa Rita Mountains. More about the painting in my watercolor blog.

After a rainy January, the weather has turned sunny and gorgeous. With all the early precipitation, we don't even have to feel bad about it. The mountains, covered in last years dead grasses reflected the sun like fields of gold, nicely set off by the blue shapes of Mount Whrightston  and Mount Baldy.


I could see snow on the higher elevations, but down in Box Canyon the temperature reached the high eighties. I met a naturalist friend and we looked for insects: He found interesting syrphids. The antennae of the males were shaped like bundles of feathers. Copestylum (Hiatomyia) plumosa? I got no photos, too bad. I hope to go back for them.




The creeks were gurgling with clear fresh water. No bugs except some Water Striders.  Bonewhite Sycamores rose ghostly in the early evening shade of the canyons.



Several dark butterflies were flying around: Mourning Cloaks, Bordered Patches and Pipevine Swallowtails. Does their dark coloration give them enough thermoregulatory advantage for an early start? 



 Already, Desert Broom was attracting scores of wasps.  These are potential queens of Paper Wasp species that overwintered, I assume. Like every year in spring, I'm confused - their coloration differs from that of the workers I'm used to seeing in summer and autumn.
   

 At Madera Canyon Lodge, a Coatimundi visited the bird-feeder area. He seemed well-fed, content and rather tame. Probably not a great situation, but I did enjoy watching him for a while. 

White-nosed Coatis in SE Arizona are the northernmost ambassadors of the south and central American genus Nasua (in German Nasenbaer). They are Racoon-related omnivores but more day-active than those (less hunting pressure, historically?. They feed on insects, lizards, roots, fruits, nuts and eggs. They are very fond of fruit, especially the manzanita berry, and obviosly don't dislike easy-picking bird seed.

  On the way home, the grasslands glowed even more and mountain shadows undulated. It's hard to decide which photo to choose.


P.S. In the meantime I found several Flickr posts of the little group of  Coaties at the Madera Canyon Lodge. I was quite dismayed to see how very obese at least one of the three regulars is.  Feeding wild animals is illegal in Arizona. But feeding birds is exempt from this law. In fact most birdlovers still believe that they are doing a commendable service to the birds. As a biologist the only value that I can see is that people might get interested and feel protective about more than just hummingbirds. Also,  for the lodge and several B and Bs in Madera Canyon the bird feeders are an intrinsic part of a lucrative business and beloved by so many visitors that it would probably be impossible to end this practice. But the feeding and overfeeding of the coaties is problematic. The feeders are alraedy positioned pretty much out of reach of even good climbers.  I hope there is a way (and I will raise the issue) to keep the spilled birdseed from reaching the ground.




Saturday, February 4, 2017

Dung Beetles - important for environment and agriculture

Scarab beetles are one of our largest and most divers beetle families. Most Arizonans are quite familiar with the day active Green Fig Beetle and smaller brown beetles of several  genera that tend to accumulate around porch lights and are often just called June Bugs.

Hercules Beetle larva

 Gardeners among us usually hate the white, c-shaped, fat grubs of scarabs that live in the ground and supposedly feed on the roots of your favorite plants. Some of them might in fact do that.

But most scarabs are decomposers, and therefore very important for gardening and agriculture. Their grubs feed on dead plant material that they digest with the help of bacterial symbionts in their widely extended guts. Hence the impression that they are fat. The strong mandibles of those often very large grubs are able to break down decaying wood and leaf matter, utilize amazing amounts of material,  and thus open it up to smaller decomposers, and finally fungi and bacteria. So eventually the nutrients will again be part of the garden soil and available for uptake by plants..

  Among scarabs, dung beetles have evolved to break down the feces of larger animals. The importance of this 'service' can hardly be overestimated.  Obviously, they are removing waste that would otherwise pose a serious health risk. For example, dung beetles help to remove harmful pathogens like E. coli from soil. But if you consider the amount of dung that  big herds of  grazing animals produce, you'll understand that the mere accumulation of this dung would eventually cover so much surface that the grasses that the herds a feeding on would be displaced by a rather sterile crust of dung.

Dung Beetles of the genus Phanaeus
Beetles in the genus Phanaeus are 'tunnelers'. They excavate tunnels beneath the very fresh dung pile and lower a portion of dung down into the ground below. There, the female will lay an egg in the brood ball and seal the chamber. The larval beetle will feed on the dung as it grows until metamorphosing into an adult and emerging.


Dung Beetles in the genus Canthon are America's typical dung rollers. With their shovel heads, they cut a spherical dung portion from the fresh pile. Most of this work is done by the male. The resource is limited, though fights between rivals happen often. A female joins a successful male, often sits on top of his prize as he rolls it in a rather straight line away from the competition. They bury the dung ball and in the underground chamber she lays an egg on it.

Although there is no longer a source in the US to buy dung beetles of any type, historically, the U.S. government sponsored dung beetle introduction programs. When the local dung beetle population did not seem to be able to handle the waste of Texas' huge Cattle herds, Digitonthophagus gazella (Gazelle Scarab) was brought in in the 1970. Of Indoafrican origin,  it is now perhaps the most widespread dung beetle in tropical and subtropical pastures. (Noriega et al. 2010).  Euoniticellus intermedius was brought to Texas from Africa. Thus dung beetles from traditional feeding grounds of big herds were introduced.  I do not know why dung beetles were not brought in from old buffalo grounds like the midwestern prairies, but instead from Eurasia and Africa. Maybe the introducers thought them more suitable for the Texas climate. The beetles proved invasive. They quickly spread throughout most of the southern U.S. 
Digitonthophagus gazella (Gazelle Scarab) and Euoniticellus intermedius, both introduced
 The introduced species are doing their job. They propagated so successfully that they are found all over Arizona by now. In fact, by now most larger dung beetles we find are of those two species. It is difficult to tell if this is harming the populations of endemic species that they compete with, but it is hard to imagine that they wouldn't. My impression is that the  two introduced species are generalists that can deal with nearly all types of soil, dung types, and exposure. They also find dung sources fast and at great distance and fly well enough to quickly move into new areas.  Where we live, for example, grazing is so poor that cattle may only be brought in every few years. Phanaeus and large Canthon species never show up, only all kinds of small Aphodines plus the two imported medium sized species depicted above.  Our endemic large Canthon imitator, the smaller Canthon indigaceus and the three Phanaeus species seem be more discriminating in their choice of habitat and not so fast at pioneering new spaces.