Announcing an Anna's Annual Arrivals Analysis
Combined Data from 2003-2009
Temporal data for 9 different Anna's hummingbird nests constructed in the same Tasmanian tree fern in San Diego, CA.

	Nest-	building	Egg-	laying	Egg-	hatching	Chick-	fledging
Year	Started	Finished	First Egg	Second Egg	First Egg	Second Egg	First Chick	Second Chick
2003	Mar 04	Mar 08	not observed	not observed	~Mar 30	~Mar 30	Apr 16	Apr 19
2004	Feb 24	Feb 28	Feb 29	After Mar 06	Mar 17	+Mar 18 dead	Apr 09	-
2005a	Feb 24	Feb 28	Mar 04	Mar 06	~Mar 22	~Mar 22	Apr 14	Apr 14
2005b	May 22	May 25	May 25	May 27	Jun 10	Jun 11	Jul 03	Jul 03
2005c	Dec 22	Abandoned	-	-	-	-	-	-
2006	Feb 26	Mar 01	Mar 07	Mar 10	Mar 25	Mar 26	Apr 19	^see note
2007	Mar 04	Mar 08	Mar 09	Mar 11	not observed	not observed	Apr 17	Apr 17
2008	Mar 08	Mar 12	Mar 14	Mar 16	Mar 31	Apr 01	*Nest gone	on Apr 08
2009	Apr 23	Apr 27	Apr 29	May 01	*Eggs gone	on May 05	-	-

+Mar 18 dead, 2004. The mother hummingbird appeared to break open the egg of the dead chick with her beak.
^Apr 08, 2006. Chick was found on the ground under nest, placed back in the nest, found on the ground again, and taken to the local humane society.
*2008 nest and chicks and *2009 eggs were presumably preyed upon by ravens or hawks which are frequently observed hunting in the neighborhood.


Timing of Anna's Hummingbird Nesting Events by Year (2003-2009)
Time in days until nest completed, eggs laid, eggs hatched, and chicks fledged.

	Nest-	building	Egg-	laying	Egg-	hatching	Chick-	fledging
Year	Started	Finished	First Egg	Second Egg	First Egg	Second Egg	First Chick	Second Chick
2003	Day 0	Day 4	-	-	~Day 26	~Day 26	Day 42	Day 45
2004	Day 0	Day 4	Day 5	~Day 11	Day 22	Day 23 (died)	Day 44	-
2005a	Day 0	Day 4	Day 9	Day 11	~Day 26	~Day 26	Day 48	Day 48
2005b	Day 0	Day 3	Day 3	Day 5	Day 19	Day 20	Day 42	Day 42
2005c	Day 0	Abandoned	-	-	-	-	-	-
2006	Day 0	Day 3	Day 9	Day 12	Day 27	Day 28	Day 52	-
2007	Day 0	Day 4	Day 5	Day 7	-	-	Day 44	Day 44
2008	Day 0	Day 4	Day 6	Day 8	Day 23	Day 24	-	-
2009	Day 0	Day 4	Day 6	Day 8	-	-	-	-
Totals:	n=9	n=8	n=7	n=7	n=6	n=6	n=6	n=4
Averages:	-	4 Days	6 Days	9 Days	24 Days	24 Days	45 Days	45 Days

Based on the data in the 2 tables shown above, for 8 different Anna's hummingbird nests built between 2003 and 2009 in a single Tasmanian tree fern in San Diego, CA, the average time to build a nest is 4 days. The average time for the first and second eggs to be laid is 6 and 9 days, respectively. The average time for both eggs to hatch is 24 days, and the average time for both chicks to fledge the nest is 45 days from the onset of nest-building.



Torrey Pines Peregrine Falcons.


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