BEE MAY 2014

Birds and Bees and Trees, Oh My! — Sierra de Guadalupe

Love is definitely in the air. The male Hooded Orioles, Northern Cardinals and House Finches have been singing their hearts out this past month in the Ficus benjamina and Jacaranda trees in the garden. And the Ospreys seem to have finally settled down with their respective mates in one of several nearby nests.

Until recently, one pair of these large fish eagles were working hard on a new nest on top of the power lines across a small canyon from us. Over a few days, intermittently one or the other osprey could be seen swooping low past the dining room window, weighed down by a huge branch in its talons. Occasionally, it would have to stop flapping briefly to readjust its load before continuing on its way to the new nest. And for several weeks, one bird or another would sit on the power pole located just on the other side of our wall, and on and off throughout the day call in a high-pitched, shrieky, almost fingernail-on-chalkboard manner. Endearing? Maybe not so much, but they are incredibly gorgeous birds. One local character can be seen regularly in the morning or evening perched on the rail of the highway bridge near downtown where it crosses the river, looking for prey far below in the water. It seems unperturbed by the semi trucks and cars roaring past.

The Carpenter bees (possibly Xylocopa californica) are also busy. These huge, iridescent black insects build nests in exposed wood, such as roof beams and posts. They also like dead palm trunks that are commonly used here for posts. They are considered to be pests because of the structural damage they can cause, but they are very interesting to observe and important desert pollinators. Apparently it is the male bees that hover at the nest entrance, protecting it and agressively chasing away other bees and even people who get too close! The antics when one male is chasing off several other carpenter bees is quite entertaining as they bob and weave all over the place, appearing to be drunk and unwieldy fliers. Fortunately the males don't sting, and the female is apparently reluctant to do so unless handled. Now that they are mating and nesting, they can often be heard buzzing around the house, looking for mates and new nest sites under the eves, no doubt. There are many on-line fact sheets and here is a good example.

Here in Mulegè, we don't have spring wildflower shows like those seen in the southern California deserts or in the Vizcaíno Desert less than 120 miles north of us, where spring wildflowers may bloom in late February and early March, many of them in the coastal and inland sand dunes (see below). However, this year we saw no evidence of the sand verbena and other tiny annuals on our trip to the area in late February to see the Gray Whales (read more about Mexico´s Gray Whales at my page).

Around Mulegé, most annual flowers and many shrubs and trees bloom as a result of the late summer rains July to September. They may continue into October or even November during good years. You can go here to see my images of the desert after Hurricane Jimena in 2009.

Our spring flowering is more subtle and extended, with the cactus leading the way as the Cardón (Pachycereus pringlei, Cactaceae) bud as early as the end of February in some places, and flower beginning mid to late March. The Cardón on the slope in front of our place are packed with buds and flowers for the 3rd year in a row, which is surprising since it's not uncommon for the Cardón to skip one or more years between flowering to replenish energy stores. No doubt, the 2012 and 2013 summer rains are helping greatly.  The plants are also looking very healthy and fat for this time of the year.

The flowers occur on the upper third or so of the stems in an arc of 270° between NE and NW. This species is trioecious, meaning that flowers can be of three reproductive states: female, male or hermaphrode (bisexual).

Of the gazillions of photos that I've taken, I'd have thought that I would have more variety in the sexes of the Cardón flower images, but so far I've only found one male, several female, and many hermaphrodite plants (above two images) in my image collection.

The other early bloomers are the two species of Palo Verde, both leguminous trees or shrubs (Fabaceae). Little-leaf Palo Verde, known locally as Dipúa (Parkinsonia microphylla) is the common, widespread, native, desert species while Mexican Palo Verde, here known as Junco or Junco Marino (Parkinsonia aculeata), is native to Mexico and is a common ornamental tree, readily escaping into riparian as well as disturbed areas around habitation.

Both trees are drought deciduous, and photosynthesize most of the year through the tissues of their bright green stems and branches. Dipúa lacks spines but has spinose (pointy) branches, and as the name implies, very small leaves (each rachis is about 2 cm long and the pinnate leaflets 2 to 3 mm long).

Junco has small spines along the stems at the base of the leaves. Each central stalk, or rachis, is straplike and 20-40 cm long and has tiny, pinnate leaflets 3-6 mm long widely spaced along it. The leaves give the plant a very wispy silhouette.

These species are in the subfamily Caesalpinioideae, which is usually characterized by flowers with 5-petaled,  bilaterally symmetrical to irregular flowers (see images below) that have a "standard" (upper) petal and 4 more or less similar "lower" petals.  Both of the Palo Verdes have clear, yellow "lower" petals.

The Dipúa's standard petal is white and after the flower is pollinated, it turns yellow like the rest. The Junco, on the other hand has a yellow standard petal with orange specks near the base (claw) and it darkens to orange or sometimes deep maroon after pollination.

It´s very dry here in Mulegé as I write this. The warm, northerly winds on and off throughout the months of March and April have certainly taken their toll. Though we do have the "off" parts, when it´s hot and damp instead. These are the times in the evenings when, as the wind drops and the humidity suddenly shoots up, the smell of damp creosote bush or Gobernadora (Larrea tridentata, Zygophyllaceae) will waft in through the open windows while the electrical transformer just a few yards down the hill starts to crackle and pop ominously. That's the time to mentally review the location of the flashlight and candles before relaxing and enjoying the heady odors of a warm desert night.

Around Mulegé — May 17

There has been so much to see this year, and so little space and time to show you. So I'm going to present a few unrelated items this time.

Sierra de Guadalupe

In late February, we took a day trip up to the mountains to see what we could see. The road has been in excellent shape for the last two winters, after it was wreaked by the heavy rains from Hurricane Paul in 2012. The road is narrow, mainly one lane most of the way, with some wide spaces here and there in case you meet oncoming traffic. In the 6 hours we spent that day traveling only 25 miles each way, we met two cars, one of course as we were climbing a steep, loose grade around a corner. But other than that, we could have been the only people on the planet.

It was a great trip up into the Sierra Guadalupe. None of us had ever gone as far up into the mountains before. I was constantly on alert for unfamiliar plants, but what I saw instead as I drove was a slightly different mixture, or composition, of most of the same plants familiar to me down near sea level around Mulegé.

The vegetation in the Sierra Guadalupe area is classified as part of the Sierra La Giganta floristic region, meaning that there are many differences in the species and plant communities compared to the Central Gulf Coast region. No doubt, if we make another trip in October or November, closer to the time of the late summer rains, we will find many unfamiliar plants with leaves and maybe even flowers to help us identify them.

We were all tired from getting bounced around inside the car for most of the day, but we returned to town quite content in having explored new territory and experienced the incomparable beauty of the sierras.

That´s it for now. I´ll be wrapping up the field season next month, as we head north for the US again. Hopefully there will be lots of lovely plants to report on. Until then, hasta luego...

Debra Valov—Curatorial volunteer