Table 1. Isotopic values of each source of food considered in the Bayesian isotopic mixing models.

Source	δ 13C	SD δ 13C	δ 15N	SD δ 15N	Tissue	Area	Reference
Landfills	-21.67	1.44	5.5	1.74	Muscle	Catalonia	[32]
Livestock	-25.68	0.19	6.07	0.40	Muscle	Ireland and Italy	[51,58]
Wild herbivores	-24.22	1.17	2.54	1.63	Muscle	Germany and Catalonia	[33,59]
Carnivores	-24.60	0.70	9.00	2.30	Muscle	Germany	[59]
Birds	-23.67	0.57	6.40	1.07	Muscle	Catalonia	[33]

For each source, it is indicated the mean of δ ¹³C and δ ¹⁵N and the standard deviation. The type of tissue sampled, the area and bibliographic reference of the study of data collection are also specified.