Swainson's Hawks, NE San Antonio:  Nesting 2006, 2007, 2008, 2009

For a summary of key dates and facts, click here.

 2006 videos of the birds are here. These are not too good
 2007 videos of the birds are here. These are better
 2008 videos of the birds are here.
 2009 videos:  none yet

2006 Photos of the birds are here.
2007 Photos of the birds are here.
2008 Photos of the birds are here.
2009 Photos of the birds are here.

2006 Daily observation log is here.(April through September)
2007 Daily Observation log is here.(late February to early October)
2008 Daily Observation log is here. (late March through 7/24)(remaining obs. not entered yet)
2009 Daily Observation log is here  (late March through present)

2006 season 
April through June, the remainder is on the summary page link above

By 4/4/2006, a pair of Swainson's Hawks had chosen a residential portion of NE San Antonio to set up a territory.
Their chosen territory, based on observations through the spring and summer 2006 is shown here.  The entire territory is either residential or commercial.  In the view, the end of the runway can be seen in the NW corner of the image, while Salado Creek can be seen to the east and outside the territory.  The red dashed diagonal street is Nacagdoches while the big solid red street is Loop 410.

During all of April the pair soared continuously in this territory, often climbing to 1000' and diving back but never landing except at one place.  That place was the south facing corner of the roof of the Gauranty Bank building near the corner of Nacagdoches and Loop 410.
Pair on the roof, as seen from inside chase bank building.
Female on the roof, as seen from Garanty bank parking lot.
Typical soaring here,  as seen from Frost Bank.

By mid-April they spent their time equally between soaring up high, perching on the south-facing roof of the Gauranty Bank building, and swooping around the canopy trees in the northern third of their territory.

This picture shows an color infrared air photo of their residential territory.  This image shows the residential nature of the territory very well.  During early May the birds became harder to spot as they ceased to soar.  They were building a nest Near the frost Bank building.  They could still be seen occasionally gliding and weaving among the canopy trees south of the Frost Bank building.

Here is an air photo of the nest sites for 2006, 2007, and 2008 in the closed canopy residential  location.  Note they chose the densest tree area within the neighborhood.  The nest sites were so dense that the nests cannot be seen from the cul-de-sac by the nest or from the office buildings above the canopy.  Frost Bank parking garage, Loop 410, Nacagdoches, and a few other buildings are labeled in yellow.

What was probably 2005 nest in the closed canopy, about 50 feet west of the 2006 nest.  This nest was refurbished and used in 2008(seen from a different angle).

In 2006, Between May 10th and May 15th the female began incubating and only the remaining adult  could be seen flying, usually low between the trees hunting food. Much of the male's time was spent perching and watching.
A favorite hunting perch was this cottonwood tree in the vacant lot adjoining the Frost bank.

From late May through June the male brought food to the female.  This food was of at least three components; small rodents the size of voles or large mice, baby birds, mostly grackles, and something smaller, perhaps cicadas.  Most of the food was baby birds.  By mid-June the male began soaring again but still hunted for food to bring to the nest.  often the male would not return immediately to the nest with food but would soar around while holding the prey in one talon.  Once in a while the bird would drop the prey from a great height and plunge to retrieve it a couple of times, before gliding back down to the nest.

The male seems to bring food to the nest about once per hour.  During June 2006, I noticed it took the male about a half hour to find food.   The male, by late June alternated his hunting between perching at low vantage points and gliding among the canopy trees.  The male has at least 4 places within the neighborhood he will land and watch for prey.  The remainder of the male's time during June was spent soaring up close to the clouds and among the departing jet planes, or perched on the roof of the Gauranty Bank building.

2007 Season
This seems to be a near identical repeat of 2006.  The 2007 nest is about 25 yards south of the 2006 nest.  The pair raised 1 fledgling.  Near the end of the season the pair did spectacular food drops to the juvenile who intercepted the prey in mid-drop.  This was after wedging prey in tree crotches, forcing him to clamber about too get it, sometimes in an adjacent tree.

2008 Season
The male arrived first, the female about a week later.  A nest in the same area was refurbished by April 28th.  This nest had been used last around 2005.  The male apparently contributed to the refurbishing since he was in it stomping around while the female was watching from a block away.  Incubation started 5/2/08. Two very active white chicks were visible in the nest on 6/18/08.  The three chicks were grown and all left the nest tree on 7/22/08, a week earlier than the two previous seasons.

2009 season
Again, the male arrived first, followed by the female several days later.  Female arrived missing two primary feathers, not typical but otherwise healthy.