Table 1. Starting models of GLM and GLMMs relating breeding performance parameters of reed warblers monitored in Cardiff Bay Wetland Reserve and Cosmeston Lakes Country Park in South Wales, UK, between 2012 and 2014.

Model	Sampling unit	Error family/link	Variables
Laying date	Nest	Guassian/identity	✓ Treatment (fed/control ✓Site ✓Invertebrate availability ✓Mean temperature ✓Mean April temperature ✓Mean wind speed ✓Total rainfall ✓Phragmites height ✓All two-way interactions
Clutch size	Nest	Poisson/log	✓ Treatment ✓Site ✓Laying date ✓Invertebrate availability ✓Mean temperature ✓Mean April temperature ✓Mean wind speed ✓Total rainfall ✓All two-way interactions
Incubation duration	Nest	Guassian/identity	✓ Treatment ✓Site ✓Clutch size ✓Incubation date ✓Invertebrate availability ✓Mean temperature ✓Mean April temperature ✓Mean wind speed ✓Total rainfall ✓All two-way interactions
Hatching success	Nest	Binomial/ logit	✓ Treatment ✓Clutch size ✓Laying date ✓Site ✓Invertebrate availability ✓Mean temperature ✓Mean April temperature ✓Mean wind speed ✓Total rainfall ✓All two-way interactions
Nestling growth	Individual nestling	Guassian/identity	✓ Treatment ✓Nestling age ✓Time of day ✓Brood size ✓Site ✓Incubation duration ✓Hatch date ✓Invertebrate availability ✓Mean temperature ✓Mean wind speed ✓Total rainfall ✓All two-way interactions
Total 1st brood productivity	Nest	Poisson/log	✓ Treatment ✓Site ✓Invertebrate availability ✓Mean temperature ✓Mean wind speed ✓Total rainfall