Effects of experimental nest treatment with herbs on ectoparasites and body condition of nestlings

Nest fumigation behavior involves the incorporation of fresh green plant fragments that contain ectoparasite-repellent volatile compounds into birds’ nests. This behavior is relatively rare among bird species, and there is ongoing debate about whether it benefits parental breeding success. In this study, we experimentally tested whether the inclusion of aromatic-herbal plant fragments in the nests of great tits Parus major affects the physiological condition of nestlings, as indicated by blood levels of hematocrit, hemoglobin, glucose, and body condition indices, such as weight and wing length. We divided the nests into two groups, adding aromatic herbs to the test group’s nests and non-aromatic plants to the control group. After the nestlings fledged, all nest material was collected to extract, identify, and count arthropod ectoparasites. Nestlings in nests supplemented with aromatic plant fragments had elevated levels of hematocrit and hemoglobin, indicating improved physiological con..., During the breeding season, nestboxes were visited every day to record laying date and the number hatchlings. From 26 nests of great tits with incubated clutches and without fresh plant material supplemented by birds on their own, we established pairs of nests according to their hatching date and brood size (±2 nestlings). Thirteen nests were randomly assigned to the experimental treatment and 13 were control broods. Three nests from the experimental treatment were lost (when the nestlings were 5-8 days old) due to predation. Starting on day two and then every other day until day 16 after hatching, a 1.5 g portion of fresh aromatic plant fragments (approximately 0.45 g of lavender Lavandula angustifolia, 0.35 g of mint Mentha sp., 0.35 g of the Immortelle Helichrysum italicum, and 0.35 g of the Common Yarrow Achillea millefolium) was supplemented in test nests and a 1.5 g portion of fresh grass Poaceae spp. was added to control nests. Both aromatic herbs and grass were placed on three e..., , # Dataset EXP 2023 herbs great tit

[https://doi.org/10.5061/dryad.66t1g1kb9](https://doi.org/10.5061/dryad.66t1g1kb9)

## Description of the data and file structure

From 26 nests of great tits with incubated clutches and without fresh plant material supplemented by birds on their own, we established pairs of nests according to their hatching date and brood size (±2 nestlings). Thirteen nests were randomly assigned to the experimental treatment and 13 were control broods. File contains nesboxes, nests and individual nestlings in both groups with physiological and reproductive data. 

Column 1 = year of the study

Column 2 = study area of the study (here only forest)

Column 3 = the number of the nestbox

Column 4 = experimental procedure; 0 = control and 1 = herbs added

Column 5 = the number of eggs in a clutch

Column 6 = the number of hatchlings

Column 7 = the number of nestlings 13 days old

Column 9 =  the number of nestlings that left the nest

Column 10 = haemoglobin level (g/l...