Cedar Waxwings at Agua Caliente in Tucson

Super Bowl Sunday at Aqua Caliente in Tucson: The Plague Birds (Pestvogel) are here. That's what the beautiful waxwings were called in Holland where I first saw them, the Bohemian Waxwing in that case. Medieval Europeans were pessimists by default. Wars, starvation, and worst of all, the plague were recurring catastrophes that nearly every generation could expect to experience. Every sudden change from the usual was seen as a harbinger of disaster. Waxwings are birds of the northern forests where they breed in large groups without individual territories. During non-breeding times they do not really migrate, but given the right conditions, they may form large swarms  that stray opportunistically into orchards or into southern areas with good berry crops. So when, every decade or so, they suddenly appeared in such masses that they were hard to miss, the Dutch took their sudden arrival as a sign of the plague.

Bohemian Waxwings in Germany

 The name Seidenschwanz (Silk Tail) in German refers to their silky plumage. This was translated into the Latin Bombicylla as the scientific name of the genus. On the wings of both the Bohemian and Cedar Waxwing  the red shaft-ends of some feathers extend beyond the barbs and look like sealing wax,  hence the English name Waxwing.

Cedar Waxwings in Gainesville, Florida, Watercolor 1991

 Like their European cousins, the American Cedar Waxwings are no true long distance migrants, but the flocks  rather opportunistically  appear at places with a rich supply of fruit. In Florida I have seen them show up to feast on ripe palmetto berries, last autumn  the mulberry trees between Green Valley and Madera Canyon were full of the birds, and now they are all over the Washingtonia Palms at Agua Caliente on Tucson's Northeast side to pick the abundance of little black miniature dates. Both mulberries and Washingtonia Palms are introduced to the desert. I am wondering how the birds originally found them, and whether there is some kind of shared flock memory that helps them find the food sources again in years of need. Perhaps the flocks originally came to feed on something more native like the berries of the Madrone Trees in the Santa Rita Mountains.

Anyway, last Sunday there was a lot of action in drooping bundles of tiny black dates that provided a nice background for the subtlety colorful birds.

About 200 birds were taking turns between feeding bouts and breaks in the nearby Salt Cedars.

They started feeding in shady spots under overhanging palm fronds when I still felt rather chilly, so if you want good sun exposure for photos, you have to get there early. Sometimes, though,  colors are truer in the shade than in the harsh sunlight.

Some very feisty Robins were also gorging themselves - hanging in the palms as well as collecting the berries from the ground.

A Common Yellow-rumped Warbler posed nicely - I have a foggy memory of a Robert Bateman painting just like this.
A Sora visited shortly and on the back path I saw and heard a Beardless Tyrannulet but another birder was pursuing it with a better camera, so I didn't want to push too close with my short lens.

Thanks to Lois Manowitz  whose flickr photos alerted me to the Waxwing invasion!

Sure Signs of Spring

An old pecan grove at the Pinal Airfield used to be a great attraction to migrating birds, a so called migrant trap. But the irrigation of that grove has been so reduced over the last years that most of the trees died. So there were not many birds, but lots of fallen branches on the ground to give insects shelter. Tellingly, several woodpeckers and a Say's Phoebe were searching for prey.

I turned some wood and found a tenebrionid beetle Triorophus sp., and a juvenile Labidura riparia (Shore Earwig) that was hiding in something reminding of the pupal chamber of a beetle. Next, I discovered several Pillbugs and a very shrunken, discolored lizard. 

Then something moved and climbed onto my hand. A moth with only stubs for wings. It's color identified it as a newly eclosed Salt Marsh Moth whose wings were still very undeveloped.

Shed skin of a caterpillar (exuvia) and pupal cocoon shown next to an adult moth 

Earlier I had found many hairy, dried caterpillar exuviae that were left from the molt that initiated pupation last fall.  The moths then hibernated in the pupa stage (Moths are, like Butterflies, holometabolic, meaning their developmental stages start with the egg, proceed through several stages as a ever growing caterpillar, to the pupa from which emerges eventually the fully formed, but not yet fully 'inflated' adult moth).

The young Salt Marsh Moth inflated its wings in a little more than 1/2 hour

The young moth squirted a stream of brown liquid on my hand, the meconium. The meconium is usually expelled when the wings are fully inflated, so I was worried that I had disturbed the moth at a critical time and caused it to lose too much fluid too early, but as I watched, the wings stretched and grew and started to resemble their final shape. To aid the process, the moth moved into a position which allowed gravity to help inflating the wings and folded them like a butterfly would - a position that is rarely seen in this moth after the wings are hardened. 

Estigmene acrea (Salt Marsh Moth - Hodges#8131) The color of the caterpillars is variable

 I have raised other moths from caterpillars before, and although I find the process magical and very worth watching, I usually miss the last stages of wing stretching because it just takes too long. This active little guy went from 'wingless worm' to flight-ready moth in little more than half an hour. 

By then the young earwig had withdrawn into a crevice, the darkling beetle was still looking for a shady place, and the lizard had recovered in the warm sunshine, filled out his wrinkly skin and regained the color pattern of his species,  the Ornate Tree Lizard.

Packrats in our Compost Bin and in Science

 In all biological questions, my husband usually refers to me. The latest was: "what do you want to do about the rat in the compost bin?"

In kitchen and yard, we religiously save all scraps of organic material to let them decompose into fertile soil in two upside down garbage bins that sit with their openings on the ground.

It works - industrious Turkestan Roaches seem to be doing a lot of the early break down, and that's no problem because the bins are far from the house in an old 4H-goat pen. The fence keeps out our Husky, Javelinas, Coyotes and Foxes, and rows of bricks around the bottom of both bins prevent most rodent intrusions. Somebody once chewed right through the plastic wall - so now there is a hardware cloth patch.

But for a couple of days there had been a packrat sitting in the cockaigne of lettuce leaves, cucumber seeds, carrot pieces, and onion peels. Gray and big eared, she wasn't shy at all - just glared at me from under the lid of the bin. I knew that my friend Ned Harris was looking for a packrat photo opportunity,  but I could tell that this background wasn't quite it.  So, a photo for myself (I'm much less critical than he) and then the release of the rat. First I tried to lift her by the tail like a white lab rat, but she desperately clung to the substrate and I could feel that the tail's loose sheet of skin would be sacrificed before I could dislodge the animal. So I just coaxed her onto a trowel, lifted her up to the rim of the bin and let her hop off . I wouldn't  try that with a wild Brown Rat (Rattus norvegicus). But this was a White-throated Packrat (Neotoma albigula), and I had noticed before that our resident females are rather calm-natured.  So now she can get back to her business of collecting Randy's cactus clippings to decorate her home. Notice those fences around single pots in the photo above? That's how we try to protect our favorites.

Photo by Doris Evans

All over the Americas, there are many species of packrats. Our backyard with its scattering of Creosote bushes and cacti is the ideal habitat for the local species Neotoma albigula, the White-throated Packrat, and not even our five dogs and two mostly indoor cats seem to be much of a deterrent.

We live in an uneasy truce with the rodents. As the name says: they collect stuff to pile on top of their nests. But the nest can be in the down-spouts of our rain gutter with lots of collectibles left on the living room window sill that happens to be part of the way to the roof. That rat had to be evicted twice.

Another one added parts of the start-plug cables of my car to its midden. I used to park in the shade of a large Ironwood Tree. As the rats prefer working in the dark of the night, I now park over special, photocell-activated lights that Randy has sunk into the driveway. So far no further electrical disasters to report.

Pack rats are also carriers of several transmittable diseases. Hanta Virus has been found in Pima County Neotoma populations, but since we are (hopefully) never exposed to a room full of dried, pulverized, airborne rat droppings that are the most likely source of infection, there seems to be no problem.

Kissing Bug, Triatoma rubida, adult and nymph

Pack rats middens are also the favorite breeding ground of Kissing Bugs. Every summer night we can find several of those, usually engorged with blood from our dogs,  around patio lights or my black light. Kissing Bugs are part of the Assassin Bug family Reduviidae. Adults usually appear from May to early July and disappear during the monsoon season. Immatures have been found crawling around even in winter. These bugs bite rats, dogs and people alike to drink their blood. They attack at night and use an anesthetic, so their bite goes unnoticed. If you don't get allergic (which can happen after repeated exposure) there seems to be no reaction to the bite itself, no itching or swelling. But Kissing Bugs can transfer the tropical flagellate protozoan Trypanosoma cruzi that causes Chagas disease. This parasite has been found in Arizona packrats. Luckily our local Kissing Bug species Triatoma rubida seem to abstain from behaviors that would transmit the parasite. (I will get back to Kissing Bugs in later blog).

Packrat populations may also attract rattlesnakes. Indeed, we had a big old Diamondback living in the entrance of a midden. I couldn't tell whether he shared it with the rats or whether he had already devoured his hosts. We were acquainted with him for years until he scared me several times too badly - by being nice, really: he just didn't rattle anymore when I was out there single-mindedly concentrating on my photography, and several times I found his big head less than a foot from my ankle or my dogs' paws. The midden in question was under a big old opuntia. I finally lost my nerve and we relocated the snake to the state land. It took less than one summer for the rats to destroy the cactus.

So there are plenty of reasons to dislike packrats. But I can't help finding them also entertaining and fascinating.

Pear Pads with Rodent damage                                                Javelina bites leave torn fibers behind

Low desert packrat species share their extremely arid and hot habitat, without access to fresh water, with a masters of desert survival, the Kangaroo Rat. But while K-rats can live on dry seeds thanks to the enormous concentration capacity of their kidneys,  packrats void copious urine.  Thus they are only able to maintain their water balance as long as they have access to their favorite high-water-content food, succulent plants like cacti and agave (Schmidt-Nielson and Schmidt-Nielson, 1952).

Middens are usually shaded by vegetation, but sometimes the rats bite of the cactus under which the nest

Their most special adaptation, which gives packrats their name and makes it possible for them to live in very hostile environments, is their ability to construct huge, insulating middens. Packrats seek rock crevices, caves or dense patches of vegetation as shelters, but they improve these by piling on sticks, pieces of cacti, bones, spent shells from guns, toys - just about anything portable that catches their eye. These piles can be conspicuous and over 2 m high in some species. Underneath this fortified den that protects from predators and buffers against temperature extremes is a burrow system with chambers serving to cache food (Packrats do not hibernate) and the small nest made from soft, shredded material.

 When we evicted the 'down-spout-rat' by turning on the water-hose I was surprised that it showed neither fear nor aggression even when cornered. Now I observed the same 'tame' behavior in our compost-bin guest. This character has probably evolved in packrats because the fortified den is a save haven for this animal that has no energy to spare for fight or flight. Packrats live under chronic energy stress due to their diet of low energy plant material (Cactus, Creosote, Juniper) much of which is also rather indigestible because it is loaded with defensive chemicals like terpenoids.  (McClure and Randolph, 1980).

Amberat, a treasure to science
So Packrats are extremely faithful to these middens that their survival depends on. Good den-sites are in short supply and the accumulation of material is costly, so generation after generation of the female line uses the same den, adding material and caching food. Over years, decades, centuries, even millennia, urine accumulated and dried in amber-like clumps under the nest - this substance is called amberat (Some starving miners around 1849 actually tried to eat the 'candy-like food'). 
Today, paleontologists and archaeologists are finding the Southwestern packrat middens a plethora of valuable information. Fossil plant pollen are imbedded in amber-like urine deposits and the whole den  is a collection of animal and plant records that reach far back into the Pleistocene.
As there are no pollen-preserving peat bogs in the Southwestern deserts, and pollen studies were limited to lake sediments in only a few locations, the study of packrat middens became one of the most important resources for the understanding of the changing biogeography of the Southwest from the Pleistocene to the present.

Literature: 
JL Betancourt, TR Van Devender, PS Martin (1990) Packrat Middens, the Last 40,000 Years of Biotic Change.  University of Arizona Press, Tucson
K Schmidt-Nielson,  B Schmidt-Nielson (1952) Water metabolism of desert animals , Physiological Review 32, 135-166
P A McClure, J C Randolph (1980) Relative allocation of energy to growth and development of homeothermy in Neotoma floridana and Sigmodon hispidus. Ecological Monographs 50, 199-219 

Wintering Birds in Avra Valley and Santa Cruz Flats

 Pima Cotton, Sorghum and Alfalfa: the Avra Valley north of Marana is flat, fertile, irrigated and heavily used for agriculture.

Dust, pesticide and herbicide bombardment and unrelenting sunshine without shade can be a real turn-off at times, so I hardly ever go there.

Migratory birds have different preferences. Thousands of Blackbirds, mostly Yellow-headed, and Lark Buntings land in freshly harvested sorghum fields.

Yellow-headed Blackbirds

Lark Buntings

Lark Sparrows

Horned Lark

Northern Harrier

Common Ground Doves

 Scores of other sparrows and Meadow Larks, too shy for good photos. But Lark Sparrows sit nicely in great light. On the side of the irrigation ditch a single Horned Lark, but I have to shoot through the windshield. Same for the Northern Harrier. Other raptors show up and disappear before I get a good look. Lots of Ravens. Little Ground Doves are courting. Spring is coming.

Of Cactus Flowers and Fruit

The flowers of chollas, prickly pears, saguaros, queen of the night and barrel cacti are strikingly beautiful but delicate and very short lived. If an individual bud opens in the early morning or even at night the flower will begin to wilt by noon with raising temperatures or even as soon as it is pollinated. If it lasts till nightfall it will most likely not open again the next day. There are cacti which go through their whole annual blooming cycle within one night and a short morning like the night blooming cereus, but most species produce enough successive flowers to keep the bloom going for a week or more. It doesn't matter how long it lasts: the bloom of the Sonoran desert cacti is a beautiful spectacle that we celebrate every year. It is also a reliable fiest: the succulent cacti are able to faithfully produce flowers even in drought years when the showy and celebrated annuals of the desert like poppies, lupines and Owl Clovers have to skip the year.

Santa Rita Prickly Pear: Only a few of these pears will ripen.

At least some rain is necessary for the cacti to follow the bloom with the more costly production of fruit. If it doesn't rain enough for too long even the fertilized flowers will just shrivel up and fall off. But in years of at least average rainfall the fruit of our desert cacti are not only at least as beautiful as the flowers but many also last much longer.

Saguaro Cactus

Carnegiea gigantea - Saguaro Cactus

After the bloom in June, Saguaro fruit grow very quickly. They stay plain green on the outside. But as soon as they are ripe in late June they burst open to form a bright red star that advertises the sweet pulp and thousands of tiny seeds to birds and insects.

StellaTucker (Tohono O'odam) harvests Saguaro fruit by pushing them down with a 12 foot pole made from Saguaro ribs

Generations of Tohono O'odam have collected the fruit to brew ceremonial wine. Midsummer dances of this tribe are a plea for good, life spending monsoon rains. By the time the storms arrive, Saguaro fruit are usually gone from the cacti and the seeds distributed by everybody who enjoyed the sweet snacks.

Mammillaria

Mammillaria grahami - Arizona Fishhook Cactus

Pretty much exactly 8 days after each summer rainstorm all our tiny Mammillarias wear crowns of pink flowers. Shortly later they produce small red-pepper-like seedpods. Just the right size to be carried away whole by Trashers, Cactus Wrens, Squirrels and even ambitious Harvester Ants.


Night-blooming Cereus

Peniocereus gregii - Arizona Night-blooming Cereus

The beautiful Queen of the Desert Night chooses a warm night in June or July to open its flowers and fill the desert with its sweet heavy fragrance. Mysteriously, all plants in a certain area appear to be synchronized, while other groups, at only about ten miles distance, follow their own internal signal. Temperature, moon phase or humidity seem of little importance, or their interaction is so complex that I don't understand their impact. Anyway, every year I scout for new plants in the desert around our place during this spectacular night. This cactus is thin-branched and much less succulent than others. Instead, it has a big underground bulb to support it during drought years. Some plants dry up completely and rest for years before they thrive out and bloom again.
Elongate big fruit develop from the pollinated flowers. This year the Pima County gardener asked me for seeds, so I covered a fruit with a paper bag. While the woodpeckers made holes into the other fruits and harvested the seed pulp in mid September,  the protected one kept growing until I lost patience in late October.


Prickly Pear

Opuntia engelmanii - Engelman's Prickly Pear
Desert Tortoise Photo by Doris Evans

Prickly pear Cacti bloom in late March and their fruit grow and ripen up to the end of summer. In good years a big Engleman's Opuntia can produce many pounds of purplish plum-sized 'pears'. They sit in tight decorative rows on the pads until in late September finally Gila Woodpeckers, Fig Beetles, ants and bees dig into the juicy flesh. Fruit that fall off are gobbled up by Desert Tortoises and Havelinas. Our neighbor boils prickly pear juice and jam, mustard and salza in big purple stained pots. With the harvest of the prickly pears, the bounty of summer is mostly gone.

Barrel Cactus

Ferocactus wislizeni - Arizona Barrel Cactus

Cacti that produce their fruit later in the year tend to hold onto them throughout the winter months. A bright yellow crown of fruit on often shoulder-high barrel cacti is a great sight when all other desert colors are rather drab. The fruit are nestled among formidable hooked thorns. Only the most daring squirrels and woodpeckers break some of them loose before their time.

Barrel Cactus seedlings 

The cactus is holding on for a good reason: The seeds, though ripe, will not germinate when it isn't warm enough. We spread seeds last year in December on moist sand in a container on the window sill, and they were just sitting there through the winter to finally produce little cacti at exactly the same time as some other seeds that we put out in March. The March seeds germinated after three weeks in the sand box.

Cholla Cacti

Cylindropuntia spinosior – Cane or Walkingstick Cholla

Cane Cholla fruit also stay on the plant during the winter months. Their bright yellow color stands out against the clear blue sky. Winter visitors often insist that they saw blooming cacti on their hikes in December.

Chain Fruit Cholla - Opuntia fulgida

The Chain-Fruit Cholla drives holding on to its fruit to the extreme. It simply never lets go, so after every blooming season more fruit are added to the ones already hanging on the branches, forming long, dangling chains. I have to cut one open: I doubt that there are seeds inside. Instead, those green fleshy members increase the photosynthesis-surface of the cactus just like leaves would. This cactus is one of the jumping chollas, and spreads its offspring by enlisting animals and people to carry broken-off pieces into new territory (zoochory). This vegetative propagation produces clones of the originals, rather than new plants. 

Christmas Cholla - Cylindropuntia leptocaulis

I like the fruit of the dainty Christmas Cholla best. Unassuming but pretty little star flowers appear in late summer, and the fruit cling to the thin green branches like red holiday decorations just around Christmas. They are juicy and sweet like strawberries. Of course, they don't last too long when they are ripe.

Water and Song Birds at Sweetwater Wetlands in January 2012

On January 7 2012, I joined the Sweetwater excursion of the local Audubon Society led by Janine Spencer. Thank you Janine it was a delightful morning! It was cold and sunny, so the light was beautiful but the contrasts were a bit harsh.

A Solitary Sandpiper poked through the mud, just one individual, but he turned up several times very close to the trail and the bridge, so I even got a video.

Hundreds of ducks, mostly Northern Shovelers were asleep along the banks or just waking up to preen themselves. The photo above is meant as a little puzzle. Can you find a pair of American Wigeons, Northern Pintails, a Ring-neck, and a female Mallard?

 This shot of a subtly patterned Gadwall is on of my favorites. I just read a quotation from an old-time hunter who called it ' just a gray duck, nearly to be ashamed of, far inferior to a Mallard' To each his own!

We also saw Ruddies, some Pied-billed Grebes (above), a Moorhen and of course many American Coots. A Sora Rail could be heard but not seen.

Sliders were basking - it got soon quite warm. I felt in my down west, carrying two cameras and binoculars.  At this time there seemed to be sufficient thermal up-drift for the local Harris Hawks to make an appearance.

I finally got a shot of one of the rats that scurry in the salt bushes. I had to consult Rich Hoyer's blog for the species id: It's an Arizona Cotton Rat (Sigmodon arizonae).

Scores of small song birds around the little pond right at the parking lot. Yellow-rumped Warblers were the most lively and numerous ones, and hard to photograph.

A group of beautiful Lawrence's Goldfinches shows up year after year. They posed nicely, but not quite close enough for my little camera.

On the ground, a Song Sparrow and a very uncooperative Abert's Towhee. But he is a character resident for Sweetwater, so his shot has to be here, no matter how blurry.

 White-crowned Sparrow females were confusing until easily recognizable males joined them. They are familiar from the feeders at home where they show up every winter in good numbers 

Photo by Muriel Neddermeyer (cropped)

A Marsh Wren entertained us with his constant chatter, but he was hard to spot and nearly impossible to photograph, so I had to borrow this photo.

As it got warmer, gnats and other insects swarmed over the water. Black and Says Phoebe (or is this a female Vermillion?) were competing for the best perches from which to start their short, fluttering forays over the creek.

After consulting Rich Hoyer for Ids, and with Robyn Waayer's input, I'm now confident to add some more of the little gray, green, and brown guys that make birding so challenging and interesting.

 A female gnat-catcher, but from this angle and with this light it's impossible to tell whether it's a Black-tailed or a Blue-gray. I think there wasn't much gray on the tail, though.

The Chestnut-sided Warbler that everybody wanted to see.  Check out Susan Beebe's excellent photo here also from Sweetwater.

A cute Orange-crowned Warbler was pruning the cat tails. Was he feeding on seeds or bugs that were hiding in there? A couple of Common Yellow Throats teased me for half an hour while they invaded the territory of a ver upset Marsh Wren. I got lots of blurred action shots. 

 My photos are taken with a 150 mm zoom lens on my Olympus SLR and with my little SP-800UZ Olympus (30 x optical zoom). I wasn't carrying a tripod around, so if there was no bridge rail or tree trunk to stabilize my aim tI was just shooting freehandedly. While these images are just good enough to document a sighting and help with ids, I'm nearly ashamed showing them here, especially in comparison with Susan's and Muriel's excellent photos. Maybe I should invest into a better camera for bird photos, but my main focus will be on insects again soon. Spring is coming early this year in the desert, the Fairy Dusters are already blooming.