Colony Development and Density-Dependent Processes in Breeding Grey Herons

Table 2

Correlation coefficients between the date of starting breeding and the breeding duration, the nestling feeding duration, or the number of fledglings in each nest.

Colony	Year	Breeding duration			Nestling feeding duration			Number of fledglings
		𝑟	𝑁	𝑃	𝑟	𝑁	𝑃	𝑟	𝑁	𝑃
Renkoji	1996
Renkoji	1997	−0.376	19	NS	0.285	16	NS	−0.495	30	**
Renkoji	1998	−0.751	24	***	−0.135	24	NS	−0.048	30	NS
Renkoji	1999	−0.647	20	**	−0.350	19	NS	−0.013	37	NS
Renkoji	2000
Tama Zoo	2000
Tama Zoo	2001	−0.422	15	NS	−0.233	14	NS	−0.591	19	**
Tama Zoo	2002	−0.329	54	*	−0.323	40	*	−0.327	78	**
Tama Zoo	2003	−0.475	79	***	−0.121	74	NS	−0.233	100	*
Tama Zoo	2004	−0.589	78	***	−0.213	76	NS	−0.218	117	*
Tama Zoo	2005	−0.614	111	***	−0.203	94	NS	−0.178	150	*
Tama Zoo	2006	−0.548	102	***	−0.342	89	**	−0.287	180	**
Tama Zoo	2007	−0.500	125	***	−0.118	106	NS	−0.311	170	***
Tama Zoo	2008	−0.743	101	***	−0.136	95	NS	−0.252	143	**
Tama Zoo	2009	−0.751	105	***	−0.311	84	**	−0.267	137	**
Tama Zoo	2010	−0.709	117	***	0.032	110	NS	−0.110	150	NS
Tama Zoo	2011	−0.702	93	***	−0.255	87	*	−0.307	120	*

NS, 𝑃>0.05; *𝑃<0.05; **𝑃<0.01; ***𝑃<0.001.