Swallow Study

Monitoring the Tree Swallow Nests in the Petaluma Public Wetlands

The swallows nesting in boxes at Shollenberger/Alman Marsh/Ellis Creek are Tree Swallows, Tachycineta bicolor.

Swallow Nesting Study

Cleaning nest box

On 5 April 2007, PWA Docent Len Nelson began monitoring 20 swallow boxes at Shollenberger and Alman Marsh, using the protocols laid out in the Golondrinas de las Americas, a joint study with naturalists ranging from Alaska to Argentina.  In late 2009, five of these boxes were relocated and six newly constructed were erected in Ellis Creek. In March 2011, two more boxes were added to those in Ellis Creek.  In the Ellis Creek oxidation ponds area, closed to the public, 10 more boxes have been monitored since 2010.

PWA’s goals are manifold:

  • Determine the usefulness of our nest boxes
  • Learn about the natural history and nesting results
  • Teach others about the importance of our nest boxes
  • Ensure nest boxes are not used by nonnative birds
  • Provide habitat for Tree Swallows and Blue Birds
  • Monitor, clean, and maintain the boxes to improve the odds of chicks fledging
  • Contribute to the Golondrinas study
  • Share data with PRBO Conservation Science and other interested parties

Details on how these nests are monitored and any questions concerning the below data can be obtained by contacting Len Nelson at lennelsn@comcast.net .

2007                    eggs    _    chicks      _   fledge __     mortality  _     houses

1st nesting              99               73                 49            24 (32.9%)
2nd nesting             59               40                 21            19 (47.5%)
Totals                    158             113                 70            43 (38.1%)            20

2008

1st nesting             89                 74                41            33 (44.6%)
2nd nesting            34                 32                18            14 (43.8%)
Totals                   123               106                59            47 (44.3%)            20

2009

1st nesting           105                  96               50            46 (47.9%)
2nd nesting            70                  55               20            35 (63.6%)
Totals                   175                 151               70            81 (53.6%)            20

2010

1st nesting           189                 171              151          20 (11.7%)
2nd nesting          132                 108    _          71           37 (34.3%)
Totals                   321                 279              222          57 (20.4%)             36

2011

1st nesting           189                 127             113           14 (11.0%)
2nd nesting          162                 134             114           20 (14.9%)
Totals                   351                 261             227           34 (13.0%)             38

2012

1st nesting           164                 149             131           18 (12.1%)
2nd nesting            47                   53               37           16 (30.2%)
Totals                   211                 202             168           34 (16.8%)             28


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