Do field margins enrich the diet of the Eurasian Skylark Alauda arvensis on intensive farmland?
Ottens, H.J. ; Kuiper, M.W. ; Flinks, H. ; Ruijven, J. van; Siepel, H. ; Koks, B.J. ; Berendse, F. ; Snoo, G.R. de - \ 2014
Ardea 102 (2014)2. - ISSN 0373-2266 - p. 161 - 174.
false discovery rate - sown weed strips - food resources - nestling diet - agricultural intensification - bird populations - breeding-season - adjacent fields - perdix-perdix - prey quality
To help restore food availability for birds, arable field margins (extensively managed strips of land sown with grasses and forbs) have been established on European farmland. In this study we describe the effect of field margins on the diet of Eurasian Skylark nestlings and adults living on intensively managed Dutch farmland. We tested the hypotheses that field margins offer a higher diversity of invertebrate prey than intensively managed crops, and that the diet of nestlings receiving food from field margins will therefore be more diverse than that of other nestlings. Field margins had a greater variety of invertebrate prey groups to offer than the intensively managed crops. Coleoptera were the most frequently and most abundantly eaten prey group by both adults and nestlings. Together, Coleoptera, Diptera, Lepidoptera, Hymenoptera and Araneae accounted for 91% of the nestling diet. Nestlings ate larger prey items and a larger proportion of larvae than adults. Almost 75% of both adults and nestlings consumed plant material, perhaps indicating a scarcity of invertebrate resources. When provided with food from field margins, the mean number of invertebrate orders in the nestling diet increased significantly from 4.7 to 5.5 and the number of families from 4.2 to 5.8 per sample. Thus, birds that used field margins for foraging could indeed provide their young with more invertebrate prey groups than birds only foraging in crops and grassland.
Lifelong consequences of early nutritional conditions on learning performance in zebra finches (Taeniopygia guttata)
Brust, V. ; Krüger, O. ; Naguib, M. ; Krause, E.T. - \ 2014
Behavioural Processes 103 (2014). - ISSN 0376-6357 - p. 320 - 326.
early developmental conditions - long-term consequences - neonatal nutrition - stress hypothesis - nestling diet - song - growth - birds - size - fitness
Long-term effects of early developmental conditions on physiological and behavioural traits are commonin animals. Yet, such lifelong effects of early life conditions on learning skills received relatively lessattention, even though they are expected to have strong fitness effects. To test the lifelong impact of theearly environment on associative and reversal learning performance, we tested zebra finches (Taeniopygiaguttata) in a reversal learning task about five years after they were raised either under low or highquality food treatments in their first month of life. The early nutritional treatment and its respectivegrowth patterns significantly influenced learning performance: Zebra finches who received a high-qualitynutrition early in life gained more weight during the treatment period but needed more trials to associatea cue with a reward. The early growth rate during the treatment phase was linked to how fast the birdsdetected the food at the onset of training in our learning task as well as to their associative learningperformance. However, in the reversal learning step of the task testing for behavioural flexibility, nodifferences with respect to early nutritional treatments or related growth rates were apparent. We showthat early life conditions directly affect the approach to our task and learning abilities over an entirelifetime, emphasizing how crucial the early environment is for understanding adult behaviour throughoutlife.