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Birding at Hornsby Bend is primarily limited to public land owned by the City of Austin and operated as the Hornsby Bend Biosolids Management Plant (HBBMP) by the City of Austin Water Utility. This facility (see map) consists of 1200 acres of ponds, woods, agricultural fields, abandoned pasture, and 3.5 miles of Colorado River bottom. The City of Austin graciously provides birders access to the HBBMP, and birders are expected to be on their best behavior. The HBBMP is where all of Austin's sewage and yard trimmings are recycled as the compost Dillo Dirt. Please observe all signs and posted regulations.

The HBBMF is open daily from sunrise to sunset.  Driving is permitted along the roads surrounding the ponds.  Stay out of the way of any heavy equipment that might be operating in the area and do not drive on any portions of the roads that might be blocked by barricades.  Do not walk on the concrete pad lining the drying basins.  It goes without saying that swimming and wading in the ponds are not allowed.  Birders are welcome to bird around the ponds, are asked to stay out of the way of plant operations, especially around the digesting tanks and facilities buildings.  Birders should also avoid walking in the agricultural fields surrounding the ponds, as these fields are used as sites for land application of processed biosolids.

That said, birders are welcome to explore and bird the rest of the property.  Most waterfowl and shorebirds can be observed from the roads surrounding the ponds.  Other roads and trails give access to the woods and Colorado River.  Surrounding fields can be scoped from the roads near the ponds.

On any given day, a knowledgeable birder should be able to find over 50 species of birds at Hornsby Bend in a morning of active birding.  This should be possible even during the slowest birding period in mid-June after all migrants have passed.  However, to maximize the number of birds seen, each of the different habitats at Hornsby Bend must be carefully scrutinized.  Birders on foot will see more birds.  A birder on foot may find over 50% more birds than a birder who birds from a car.  Likewise, a birder spending more time will see more than a birder making a quick visit.  Generally, four hours should be plenty of time to visit all of the habitats, while a quick trip of an hour and a half should be enough time to see most of the birds around the ponds.

Ponds
The number of birds in and around the ponds can be quite variable from season to season, day to day, and often changes hourly.  The number and variety of birds found is often a function of season, weather, and water-level conditions.  You should be able to find most birds listed in the species accounts as fairly common to abundant, but the dynamics of local conditions and local bird movements makes total prediction impossible.  This can be frustrating if you miss a fairly common bird.  However, it is frequently offset by the joy of seeing an uncommon or rare bird that just happens to be moving through the area.

The following are some general guidelines and suggestions for birding the ponds:

• Take your time.  Move slowly and look carefully at every bird.  Take time to notice where the birds are and what theyíre doing.  The more time you spend, the better chance you have of seeing those birds that might be moving around or present but out of view.  If you see diving ducks or grebes, watch to see that you arenít missing some that might be diving.  If you find groups of shorebirds, look through the flock several times to avoid missing that unusual bird that might have been hidden behind the grass on your first scan of the flock.
• Look in each of the ponds.  Pond 2 usually has the most diving ducks and grebes when water levels are high.  Pond 1E usually has fewer birds, but sometimes rarities passing through the area stop on this pond before moving on.
• Look for marshy areas.  Marshes and mudflats in the ponds can be present depending on current water levels and pumping schemes.  Pond 1W has had great mudflats and marshes at times, as have Pond 2 and Pond 3.  These marshes and mudflats can be very attractive to shorebirds, waders, and resting waterfowl.  Large flocks of blackbirds congregate in the marshes and lucky observers have seen rails and bitterns by scanning the marshes.
• Look for birds hiding under overhanging tree limbs around Pond 2 and for birds perched on dead limbs projecting above the surface from submerged trees.  These are often used as roosting sites or resting areas for birds on the move and birds seeking respite from the weather.
• Check out the trees and vegetation around the ponds for migrating songbirds.  Many good birds have been seen in these trees, including such locally rare migrants as Kentucky Warbler and Black-billed Cuckoo.  Marsh Wrens are found along the dike a few times each winter.

In order to see the most birds in this area:

• Take your time.  Look carefully at each bird.  Sometimes flocks will move around.  Watch where they go and patiently look over each basin before moving on.
• Pay attention to different micro-habitats in each basin.  Look in both wet and dry areas, bare and vegetated areas.
• Pay attention to how birds are reacting to the weather.  The basins are very open and exposed.  Birds may be hiding behind windbreaks during a storm or frontal passage.  Some birds might be seeking more shaded areas during the middle of the day.
• Look for both active and resting birds.  Some birds may be actively feeding in the open, but resting birds might be settled down and harder to see.  Small sandpipers often use the drying basins as final staging areas before continuing their migration at dusk.  These birds may rest together in large groups during late afternoon before taking off.

There are several ways to make sure you see the most birds along the river trail:

• Take your time.  Again, moving slowly is your best strategy for seeing birds.
• Listen for flocks of birds.  Many migrants and winter resident birds will be moving around in loose flocks or feeding guilds.  If you can locate their call notes, you may be able to more easily find them as they move around.
• If you find a group of feeding birds, stay with them as long as possible.  Many of the less common species may be only present in small numbers or only loosely associated with these flocks.  If you are patient, you will have a better chance of seeing all of the birds associated with each flock.
• Be aware of micro-habitats.  The woods are not homogeneous.  Birds will be utilizing the plants and areas that best suit their needs.  The more you know about a bird and its habitat requirements and feeding habits, the better chance you will have of locating it in the woods.  Check out all layers of forest vegetationóunderstory vegetation, mid-story in the trees, and upper layers of the forest canopy.
• Watch to see how birds are responding to weather conditions.  Good birding can be had during a rainstorm during migration, but can be difficult on a hot, clear day.  During the hotter portions of the day, look for birds in more shaded areas with greater tree canopy coverage or in thick brush.  Birds that are easily seen during mild weather are often present when it gets too hot, but they may be hard to find as they take it easy in the shade.
• Time your visit to coincide with optimal weather conditions.  In Central Texas, the most migrant songbirds will usually be found after the passage of a front or storm system that grounds birds moving during the night.  When weather is nice for several days, migrant songbirds will fly over Central Texas without stopping.  However, when there are storms, migrant songbirds will stop in the area until conditions for migration improve.  Your chances of finding migrant songbirds at Hornsby Bend will improve if you walk through the woods the day following a storm.
• Watch the river.  Many birds fly up and down the river.  They can best be seen by patiently sitting at the end of the island view trails.  These overlooks are shaded during the summer, and provide a good place to rest while you watch to see what might be moving along the river.  Night herons and cormorants are most often seen along the river.  All three species of kingfisher have been seen along the river here at various times.

The abandoned pasture area north of Pond 3 has many scrubby areas that are good for sparrows.  Harris's Sparrows are often found here in winter, and winter rarities here have included Sedge Wren, Vermillion Flycatcher, and Say's Phoebe.

Flyovers
Many birds at Hornsby Bend do not stop during migration, but can be seen as they pass overhead.  While birding the other areas at Hornsby Bend, make sure to take time to watch the sky.  The horizon north of the ponds can be especially fruitful, so be sure to check that area while scanning the drying basins.  Many birds that are only rarely seen to land at Hornsby Bend are actually fairly commonly seen or heard flying overhead.  Upland Sandpiper, Long-billed Curlew, Sandhill Crane, and Mississippi Kite are regularly seen and heard flying overhead during migration, though they are only rarely seen to land near the ponds.  Such rarities as Magnificent Frigatebird, Golden Eagle, and Wood Stork have been seen passing overhead.  Pausing to scan the horizon and look overhead will help you to see more species and to appreciate the wonder of migration as birds stream overhead and out of sight.