European Starlings Regurgitation of Russian olive seeds.mpg

Both federal (permit MB019065) and state (permit: 10TRb2006) permits were acquired prior to testing.

On December 14th, 2010 20 European Starlings were captured at a cattle feedlot outside of Platteville, CO (40°12' 39.84"N by104°52' 15.84"W) using modified Australian Crow traps. All birds were transported to the USDA-NWRC Outdoor Aviary Research Facility (OARF) and housed in individual testing cages (0.9 m × 1.8 m × 0.9 m). A maintenance diet was provided daily (ad libitum) to all birds. Water was also provided daily (ad libitum) to all birds throughout the study. Both food and water were simultaneously presented to the birds through the left hand door of the cage

Along with the maintenance diet, Russian olive fruits were presented to the birds in a free choice mannor. In free choice, birds were presented with 25 Russian olive fruits at a time in small clay dishes, through the right hand door of the cage and left for 24 hours. The birds were given the option to freely feed on the seeds at their leisure. Depending upon the bird feeding behaviors, each bird was held until it had consumed a total of 50 seeds for the test, or a grand total of 1000 seeds. Free choice testing was carried out over a 1-week period. Water, maintenance diet, and test fruits were checked every morning at 0700 hours (7:00 am MST).

Feeding was monitored using a camcorder mounted on a tripod facing the cages for further analysis on feeding behaviors. Video cameras were positioned either on tripods on top of the cage or were attached to the sides of the cage. Video was recorded over an 11 hour time period, just after seeds were introduced to the birds in the morning. Video was screened after the testing to determine feeding behaviors.

Paper tray liners were removed from the cages every other day for seed collections from the fecal matter and regurgitations. Seed passage was determined by screening the feces and regurgitated seeds for those that had been stripped of the fleshy perianth, which constituted a "cleaned" seed. Seed passage was determined by screening the feces and regurgitations by collecting the respective sample from fecal trays. Russian olive seeds were identified from the feces and distinguished from other seeds consumed. Seeds were considered scarified if they were defecated or regurgitated, based upon their morphology and the digestive processes that occurred.

This video shows is the continuation of video 1, showing a Euroipean Starling activly feeding upon Russian olive seeds presented to it. Elapsed time betwee nth two videos is 26 minutes and 43 seconds. We see the same birds landing near the feeding bowl, and after several efforts regurgitates a Russian olive seed. This same behavior was documented throughtout the testing for the other birds, with the majority of Russian olive seeds consumed being regurgitated within 20 to 50 minutes post feeding.

Category:

Science & Technology

Tags:

• European
• Starling
• feeding
• behavior
• on
• Russian
• olive
• seeds