photo by Len Nelson

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.

On 5 April 2007, PWA Docent Len Nelson began monitoring 20 swallow boxes, located in Shollenberger and Alman Marsh, in a joint study, called Golondrinas de las Americas, 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              boxes
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