Field notes #6

#020616 John D MacArthur Park

Survey start: 12:00pm   Survey End:  1:30 pm

Official low tide: 12:20 pm

Conditions: clear 78°

Bird Counts (JDM)
	Count	Behavior observed	Disturbance
Great Egret	1	F
Great Blue Heron	1	F
Little Blue Heron	1	F	H,D
White Ibis	1	FO
Roseate Spoonbill	1	F
*F=foraging	R= roosting/resting	FO = fly over

Notes: Finally there were mud flats exposed at low tide. Surprisingly the only birds utilizing them as a resting or foraging area were pelicans and seagulls. The few Ciconiiformes that were recorded, were foraging along the mangrove tree lines. This seems to be the norm for this particular location this season.

All of the birds using the inter tidal mud flats were displaced by human disturbance. At the time of the survey there were three paddle boarders, one kayaker, two wading humans and a dog. The latter set up camp on the flats area and were fishing. After walking to the northern end of the survey area, six more paddle boarders were recorded. Turning to the other side looking directly into the Lake Worth Cove (interior) side of the park; at least 4 more kayakers were recorded. There were no exposed mud flats in the interior of the park on this particular day.

As the researcher left the area, one roseate spoonbill was recorded foraging in a very remote section of the park that had no access by humans.

According to Drake (2007, cited by Vegvari, et al., 2011) Human disturbance can play an important role on the distribution, ecology and behavior of animals. Peters and Otis, 2006, conducted studies to determine if human disturbance that causes flushing behavior translate into site avoidance. More research is needed, but this seems like it could be an early explanation of why there are very few birds in the open areas of the park. Water sport traffic has been steadily increasing in this area over the years (personal experience).

The other factors that should to be researched are population decline of overall wading birds in South Florida and changes is food availability/quality.

References:

Zsolt Végvári, Zoltán Barta, Pekka Mustakallio, Tamás Székely, 2011. Consistent avoidance of human disturbance over large geographical distances by a migratory bird. DOI: 10.1098/rsbl.2011.0295

Peters and Otis, 2006. Wading Bird Response to Recreational Boat Traffic: Does Flushing Translate into Avoidance? http://obpa-nc.org/DOI-AdminRecord/0063794-0063802.pdf