Monitoring of great tits reproductive success, body condition and infection status

We investigated the impact of haemosporidian parasite infections on reproduction and survival of two populations of great tits (Parus major) located in two study sites in Switzerland: Dorigny and Monod. Birds were sampled during the breeding season for 12 consecutive years (2005-2016). Nest boxes were regularly inspected from mid-March and laying date (1 April = day 1), clutch size and fledging success were recorded. Adults were marked with an individually numbered aluminium ring (Swiss Ornithological Institute, Switzerland), weighed with an electronic balance and the tarsus was measured using digital callipers (0.01 mm). Adult sex and age were determined using plumage characteristics or ringing records when available. In order to investigate avian haemosporidian infection, 30-50 μl of blood were sampled by brachial venipuncture. Parasites were detected from blood samples by nested PCR. Nested PCR products were sequenced and identified by performing a local BLAST search in the MalAvi database. Because Plasmodium and Haemoproteus gene fragments were amplified with the same primer pair, we were not able to differentiate co-infections by Plasmodium and Haemoproteus lineages from mixed infections between Plasmodium or Haemoproteus lineages.