Discoveries at Boyce Thompson Arboretum

Almost four years to the exact date I lasted visited the gardens, I returned to Boyce Thompson Arboretum near Superior. Pulling into the parking lot, I was immediately surprised by one big change: the name. And later in the morning, I'd be even more surprised by several new bird discoveries.

The property is no longer a state park, having recently separated from a tripartite agreement with Arizona State Parks and the University of Arizona. In addition, the garden has significantly expanded after absorbing the Wallace Desert Garden's entire collection of plants and trees.

In a Herculean effort spanning six years, thousands of specimens were successfully relocated from their North Scottsdale home to thirteen presumably undeveloped acres at the southern end of Boyce Thompson. In addition, one-and-a-half miles of trails were added to the park's already extensive network of paths. As a result there is an endless list of reasons and ways to explore the almost 400 acres of desert flora.

Nestled along Queen Creek, below scenic Picket Post Mountain in Tonto National Forest, the arboretum is an easy one hour drive east from central Phoenix. The grounds feature various thematic landscapes to showcase a vast plant kingdom collection, including a eucalyptus forest, a Chihuahua Desert exhibit, a grove of fruit trees, and a man-made lake. Pathways guide you through these habitats, or, if you prefer, a hike on High Trail leads you above them all into the open Sonoran Desert.

On my late April return, both wildflowers and cactus flowers were resplendent. At 2,400 feet, this location is higher than most of the surrounding desert. (Phoenix is at just over 1,000 feet for comparison.) So the blooms might have just been getting started or maybe the area was lucky to get more winter rain than the rest of us in the parched state.

The preserve owes its existence to mining magnate Colonel William Boyce Thompson, who donated his winter house and its surrounding garden to the arboretum in 1928. And now thanks to the contributions of Henry B. Wallace, new thematic collections based on South American and African deserts, to name just two, are featured.

But as usual, I visited the park for the birds and I wasn't disappointed. I was quickly struck by the abundance of phainopeplas in the spindly trees in the oldest Chihuahua Desert habitat, and then by the many northern cardinals populating the dense forest canopy above the Main Trail. Black-throated sparrows were especially prevalent in the main cactus garden and in Boojum Cove, named after the unique Baja California relative of the ocotillo. Meanwhile tiny verdins seemed to be everywhere, calling in peeps as they foraged for insects. While it's possible to find all four of these bird species in the deserts closer to Phoenix, I was amazed by the high density of them in the arboretum.

However one desert bird that stood out above the others was the broad-billed hummingbird. The arboretum's location may be his most northwest domain, so the spot is the easiest way for someone from the Valley to see him. His bill and torso are quite different - with an orange beak, a cobalt blue neck, and an emerald green torso - than Phoenix's local hummingbirds, the Anna's and the Costa's, whose most vivid colors are found exclusively on their gorgets and heads.

While I didn't see any Costa's, I did see a number of Anna's, and, surprisingly, a female or immature male Rufous hummingbird. This species should be on its way north this time of year, to breed in the Pacific Northwest. Normally the birds follow a path close to the coast, traversing the Rocky Mountains and Arizona on their voyages south starting in July. The individual at Boyce Thompson possibly wintered over at the park like another recently did at Phoenix's Desert Botanical Garden.

However I was especially blown away by the number and variety of migratory songbirds I identified and photographed closer to Queen Creek and in the brand-new Wallace Desert Garden areas. As I admired an array of blooming cacti and palo verde trees, a raspy call of an oriole attracted my attention. Shielded by a tree's dense foliage, it was impossible to definitively identify as a hooded oriole until I later photographed a pair closer to the parking lot.

Crossing the very dry creek over one of the garden's several bridges, the panoramic view of the rugged mountains to the south brought additional chills on an an uncharacteristically cool, cloudy morning. Up the steep mountain slope, I identified several lazuli buntings crowding the skinny arms of blooming ocotillos. Later, along the nearby Baja Desert Trail, I snapped some photos of a lone male, handsome with his bright blue head.

Also on that pathway I encountered a few migrating warblers, most notably my first male Townsend's. He's a striking fellow, with bold black and yellow stripes on his head and neck that made me think of a bumblebee. Even brighter was another male bird, a yellow warbler showing his rusty breast streaks. Meanwhile more numerous yellow-rumped warblers, often nicknamed butter butts, flitted through the mesquite trees.

Gentle mews sounded nearby, familiar sounds in the summer within Arizona's woodlands. Not long after, I identified the source, a male black-headed grosbeak - one of several I'd see nearby - in a distant tree. It's around this time of year when I've observed flocks of them, usually males, stopping at my summer cabin in Prescott. Their annual migration from wintering grounds like Mexico's Baja California to northern forests is clearly in process. It seemed fitting that this pack's stopover was in the park's familiar Baja desert landscape.

Orioles, buntings, warblers, grosbeaks: I timed my late April visit to Boyce Thompson Arboretum and, of course, the newly relocated Wallace Desert Garden almost perfectly. Spring migration is underway, on display in all its colorful glory, just a short drive away in Superior, Arizona.