In Search of Grosbeaks

Having learned that blue grosbeaks were recently sighted at Eagle Bluffs Conservation Area, a friend and I searched for them on our morning visit to that fabulous floodplain refuge.  As is often the case in nature, we failed to locate our quarry but saw many other species in the process; indeed, we encountered more than 45 avian species during our two hour visit.

Among the morning highlights was a large flock of American white pelicans, an abundance of great blue herons, a few bald eagles, a handful of great egrets and the usual mix of summer songbirds, dominated by indigo buntings, dickcissels, tree swallows and, of course, red-winged blackbirds; other sightings included yellow-billed cuckoos, eastern phoebes, eastern kingbirds, Baltimore and orchard orioles and a lone blue-gray gnatcatcher.

Fortunately, blue grosbeaks often stick around to raise a second brood and we should have more opportunities to observe these attractive summer residents before they depart for Central America and the Caribbean.  Whether those attempts will be fruitful remains to be seen but uncertainty fuels the joy of birding.

Dickcissel Days at Eagle Bluffs

Driving through Eagle Bluffs Conservation Area this morning, it was clear that the transition from spring migrants to summer residents is well advanced.  Waterfowl were limited to Canada geese, wood ducks, a small flock of blue-winged teal and a few mallards; shorebirds, recently represented by large, mixed flocks are now limited to killdeer and spotted sandpipers.

With the exception of great blue herons, indigo buntings and the ubiquitous red-winged blackbirds, dickcissels were the most conspicuous birds this morning, delivering their distinctive song from the tops of reeds or shrubs; favoring open grasslands, pastures and weedy fields, these vocal, sparrow-like birds have recently arrived from wintering grounds in Central and South America.  They feast on both insects and seeds and will soon pair off and build a nest in the tall grass; 4-6 eggs are generally laid.

As the summer heat builds, dickcissels and other open country birds will dominate the scene as woodland species retreat to the cool shade of forests or riparian groves; already, these tree-dwelling birds are heard more than seen, active behind a dense canopy of leaves.  Throughout the summer months, those hoping to see these birds must arrive early or late in the day, when solar radiation is less intense and cool air settles across the floodplain.

Visitor from the Desert Southwest

On my usual birding walk at South Platte Park this morning, sightings were unremarkable except for a large number of yellow warblers and the presence of an ash-throated flycatcher.  The latter bird, rare along the Colorado Front Range, is a summer resident of the Desert Southwest, from western Colorado to California and from the northern Great Basin to Mexico.

Unlike most flycatchers, ash-throats generally snare their prey from foliage or directly on the ground; large insects, such as beetles and grasshoppers, are favored but they also consume berries and small lizards.  Nests are placed in the cavities of trees, fenceposts or nest boxes and two broods are raised each year.  Wandering widely during migrations, ash-throated flycatchers sometimes turn up on the East Coast; most winter in coastal regions of Mexico and Central America.

This morning's visitor was feeding on a wooded hillside, west of Eaglewatch Lake; on their home summer range, they are best found in pinyon-juniper or mesquite woodlands, along desert streams or in the canyons of desert ranges.  Adapting well to human habitation, ash-throated flycatchers are gradually expanding their territory and may soon be more common along the Front Range.

The White-tailed Kite

One of the highlights of our recent trip to California was our first sighting of a white-tailed kite, at Humboldt Bay National Wildlife Refuge, just south of Eureka.  Perched in a small grove of trees amidst an extensive wetland, the kite resembled a snowy owl (though out of place and out of season).

White-tailed kites are permanent residents of wooded grasslands and marshlands along the Pacific Coast (from Oregon to Baja), in southern Texas, in southernmost Florida and throughout Mexico, Central America and South America.  Formerly known as the black-shouldered kite, this light-colored raptor often hovers while hunting; small rodents are its favored prey but it also consumes snakes, lizards, frogs and large insects.  Breeding pairs generally produce four offspring each year and the population and range of these beautiful predators appears to be expanding.

It's one thing for a seasoned birder to discover a new life species by patiently stalking small songbirds in dense vegetation and quite another to be confronted by a theretofore unseen raptor, sitting in the open for all to see.  It was as if nature was extending a gift, a reward of sorts for years of enduring stiff necks, cold feet, insect bites and other maladies common to birders.  The gift was sincerely appreciated.

Counting on the Coast

Today was designated Global Big Day by eBird, an effort to assess the health and diversity of avian populations across the planet.  Since we planned a morning visit to Mendocino Coast Botanical Gardens, just south of Fort Bragg, California, I decided to submit my observations from that location.

As we walked through the fabulous gardens, more birds were heard than seen but the wide diversity of foliage attracted an excellent variety of species; in addition, since the gardens extend to cliffs above the Pacific, a number of sea birds were observed.  Highlights of the morning count (which totaled 30 species) included pigeon guillemots, pelagic cormorants, Allen's hummingbird, olive-sided flycatchers, Steller's jays and a large number of white-crowned sparrows.  While my contribution to Global Big Day was modest, I was honored to participate and certainly enjoyed the experience.

South of the Gardens, we visited a magnificent sand dunes ecosystem at Manchester State Park and enjoyed a long, scenic hike to sea cliffs at Salt Point State Park.  Sea fog slowed our journey to Jenner where we turned inland, climbing along the beautiful Russian River; passing through the Coast Range, we escaped the fog and settled in a hotel room along Route 101.  Tomorrow we plan to visit the Point Reyes National Seashore before heading into San Francisco.

Birding in Bad Weather

Since we are leaving on our California road trip tomorrow, I decided to get in one more visit to South Platte Park.  While recent visits to the preserve occurred on warm, sunny days, this morning promised a different experience; low clouds, chilly air and a steady northeast breeze greeted me at the parking lot.

Despite these conditions (and, indeed, because of them), birding was excellent at the floodplain refuge.  Violent-green swallows were especially abundant, strafing the lakes and the woodlands; other sightings of note included 55 yellow-rumped warblers, 17 yellow warblers, 6 yellow-breasted chats, 4 western tanagers, a few chipping sparrows and a lone great horned owl that stared at me from a lakeside tree.  In all, my two-mile walk turned up 33 species, better than my counts on the warm, sunny days.

A gray overcast produces lighting that mimics dawn and dusk, when many species tend to be most active.  In addition, the chilly air invigorates birds and mammals alike, stoking the drive to move and to feed.  As a consequence, birding is often most productive on days that are less appealing to birders; today's visit to South Platte Park reinforced that fact.

An Ibis Squadron

Returning to South Platte Park this morning, I found that the yellow-rumped warbler invasion had diminished but those active insectivores were still abundant in the trees surrounding Eaglewatch Lake; my official count today was 93, less than a third of my estimate two days ago.  Joining them were an increasing number of summer residents (especially house wrens and yellow warblers) and the usual mix of late spring visitors.  A flock of American white pelicans soared above the refuge, an osprey fished on the open waters and the last of the wintering ducks had apparently left for northern breeding grounds.

This morning's highlight was a squadron of 16 white-faced ibis, moving in tight formation from southwest to northeast.  Having wintered in Mexico or along the Gulf coast, these western ibis are on their way to shallow wetlands across the Northern Plains, stopping to rest and feed on small fish and aquatic invertebrates en route; they generally appear along the Front Range in late April or early May.

Engrossed as I was with counting songbirds on the meadows and in the trees, the appearance of the ibis was both a pleasant diversion and an inspiring sight.  Like the flocks of migrant geese in spring and fall, they evoke a spirit of freedom that most humans can only begin to appreciate.

Invasion of Yellow-Rumped Warblers

Hoping that my second e-Bird checklist for South Platte Park would significantly exceed my first (see A Disappointing Survey), I headed down to the floodplain refuge on this cool, sunny morning.  Taking my usual 2-mile loop hike, I encountered 30 species, a modest improvement from last month; however, the count included two ospreys, a flock of Franklin's gulls, a tardy group of female buffleheads, a lone loggerhead shrike and a flock of 17 barn swallows, perched in a small tree and presumably exhausted from their migration.

But the highlight of this visit was a tremendous number of yellow-rumped warblers (I estimated 300), foraging in almost every tree that graces the southern section of the refuge.  Indeed, their numbers were so great that the movement of these small insectivores distracted me from other species that I attempted to locate.  Per records provided on e-Bird, this count is more than double the previous maximum for any site in Colorado this year but it doesn't come close to the U.S. e-Bird record of 63,600+ observed at Cape May, New Jersey in the autumn of 2010.

After wintering across most of the central and southern latitudes of the U.S. and Mexico, yellow-rumped warblers return to breeding areas in the western mountains of North America and across Alaska, Canada and northernmost regions of the Lower 48.  During their spring and fall migrations, they often travel in large flocks, a fact that was certainly confirmed at South Platte Park this morning.