Morphological plasticity reduces the effect of poor developmental conditions on fledging age in mourning doves

Abstract

Developmental plasticity can be integral in adapting organisms to the environment experienced during growth. Adaptive plastic responses may be especially important in prioritizing development in response to stress during ontogeny. To evaluate this, I examined how developmental conditions for mourning doves related to early growth and how this affected fledging age, an important life-history transition for birds. The life history of mourning doves is consistent with strong selective pressure to minimize fledging age. Therefore, I predicted that in the face of nutritional stress associated with experimental brood-size increases, young would prioritize growth to structures that promote early fledging to reduce the effect of slowed overall growth on fledging age. Increasing brood size slowed overall structural growth of nestlings and affected the relative allocation of growth among different body parts. Total wing area was the best predictor of fledging age and individuals from larger broods had larger wings relative to overall body size. Although nestlings from larger broods fledged at later ages owing to slower overall growth, prioritization of wing growth reduced this effect by an estimated 1.6 days relative to the delay if plasticity among body parts had not occurred. This was an 11 per cent reduction in the predicted developmental time it took to reach this important life-history transition. Results demonstrate that preferential allocation to wing growth can affect the timing of this life-history transition and that morphological plasticity during development can have adaptive near-term effects during avian development.

Growth and development of house sparrows (Passer domesticus) in response to chronic food restriction throughout the nestling period

“…overall, food-restricted nestlings fledged at later ages compared with controls (due to slower overall growth), yet the food-restricted birds that prioritized wing growth over growth of other body tissues mitigated the delayed fledging effects associated with their reduced size (Miller, 2010). In both our control and food-restricted house sparrows, we observed rapid increases in tarsus length during the first week post-hatch, followed by slowed growth to day 12.…”

“…Therefore, if growth is not maintained when circulating levels of growth hormones are high, negative and permanent consequences for bird fitness and survival may result. Reduced size because of food limitation has been shown to delay fledging time (Cruz and Cruz, 1990;Searcy et al, 2004;Takenaka et al, 2005;Miller, 2010), decrease social rank (Richner et al, 1989) and decrease predicted recruitment and survival of birds in the wild . A study of mourning doves showed that,…”

“…A number of studies have shown that altricial (Lepczyk and Karasov, 2000;Moe et al, 2004), semialtricial (Negro et al, 1994;Reid et al, 2000) and semi-precocial (Takenaka et al, 2005) birds that are food-restricted during the nestling period maintain skeletal growth despite reductions in the mass of the whole body and soft tissues. Some studies of chronic food restriction show that if birds receiving inadequate quantities of food during the nestling period decrease structural growth, then decreased competitive ability within the nest, delayed fledging and reduced recruitment and survival after fledging may result (Cruz and Cruz, 1990;Searcy et al, 2004;Mock et al, 2009;Miller, 2010). Thus, prioritizing growth of skeletal structures during the growth period may prevent long-term negative effects of food shortage.…”

The effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function, and life-history

“…Condition is thought to be indicative of an animal's health and well-being and related to fitness (Peig and Green, 2009). In developing animals, condition could be an important indicator of competitive ability within the nest, maturation, and survival and recruitment following fledging (Miller, 2010;Mock et al, 2009;Searcy et al, 2004). We assessed condition using residual body mass (mass divided by tarsus length) and the scaled mass index (Peig and Green, 2009;Peig and Green, 2010).…”

Within- and Among-Observer Variation in Measurements of Animal Biometrics and their Influence on Accurate Quantification of Common Biometric-Based Condition Indices

“…Such a low weight at fledging is expected when the life history has evolved under selective pressures to minimize age at fledging. This can happen in the case of heavy predation, high parasite load, or starvation during the chick phase (Miller 2010). Crab Plover chicks have a very low parasite load (F. H. Teyefeh, pers.…”