TABLE 3.

Mothers at nests with supplemented calcium produced and hatched more and larger eggs, with some variation by year, as indicated by the model set and rankings exploring the importance of calcium supplementation (“Treatment”) and “year” on mean clutch size per nest, mean hatching success per nest, and mean egg volume per nest in Tree Swallows at a high‐elevation valley in northern Colorado during 2017–2018. The number of parameters (K), −2 log‐likelihood (−2LL), and model weights (w _i ) are shown for each model and the models are ranked by their AICc differences relative to the best model in the set (∆AICc _i ). The minimum AICc value for mean clutch size per nest was 482.53, for mean egg volume per nest it was 601.69, and for mean hatching success per nest it was 482.53. “Box” was included as a random effect in each model.

Dependent Variable	Model	K	∆AICc i	−2LL	w i
(A) Mean Clutch Size per Nest	Treatment	4	0	−109.39	0.44
	Treatment × year	6	11.96	−107.65	0.24
	Treatment + year	5	14.12	−109.33	0.15
	Intercept	3	18.41	−111.66	0.14
	Year	4	21.13	−111.75	0.04
(B) Mean egg volume per nest	Treatment × year	6	0	−277.84	0.97
	Treatment + year	5	6.92	−282.57	0.03
	Year	4	19.64	−290.15	0.00
	Treatment	4	20.41	−290.53	0.00
	Intercept	3	32.22	−297.61	0.00
(C) Mean hatching success per nest	Treatment × year	5	0	−236.01	0.36
	Year	4	0.74	−238.74	0.25
	Intercept	2	1.34	−240.15	0.18
	Treatment + year	4	2.36	−238.39	0.11
	Treatment	3	2.62	−239.68	0.10