Average Number
of Days on the Wintering Grounds
Eastern Flock, First Aircraft-led Cranes to Depart
The six young cranes in the Class of 2015 have been on their wintering grounds since February 6, 2016, after the latest aircraft-led arrival in the project's history. Calculate the number of days to the first departure from the wintering grounds. How does it compare with aircraft-led cranes in previous years?
Year |
Days
Spent on Wintering Grounds ( first birds to depart) |
|
| Class
of 2015 (St. Marks NWR) |
55 days** | |
| Class
of 2014 (St. Marks NWR) |
91 days* | |
| Class
of 2013 (St. Marks NWR) |
92 days | |
| Class
of 2012 (St. Marks NWR) |
107 days | |
| Class of 2011s (Wheeler NWR) |
72 daysarday |
|
| Class of 2010 | 96
days 0
days (St. Marks NWR) |
80 days (Chassahowitzka NWR) |
| Class of 2009 | 70
days (St. Marks) |
75 days (Chassahowitzka) |
| Class of 2008 | 72
days (St. Marks) |
60 days (Chassahowitzka) |
| Class of 2007 | 57 days | |
| Class of 2006 | (Florida Storm: no survivors) | |
| Class of 2005 | 106 days | |
| Class of 2004 | 104 days | |
| Class of 2003 | 113 days | |
| Class of 2002 | 121 days | |
| Class of 2001 | 126 days | |
* March 22, 2016 was the departure date for ONE of the juveniles (#2-15), in the company of four older cranes leading the way.
* March 11, 2015 was the departure date for ONE of the juveniles (#7-14), in the company of two older cranes leading the way. The other five members of the Class of 2014 left April 3.
Journal
or Discussion Questions
The number of days on the wintering grounds
is calculated from the arrival date to the first bird's departure date.
- What do you need to know in order to figure the average number of days spent on the wintering grounds for each group of birds?
- What is the average number of days on the wintering grounds for all years in which ultralight-led cranes have departed on spring migration?
- What factors might explain the year-to-year differences?
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