Development of parameters influencing blood oxygen-carrying capacity in nestling doves

Variation in growth profiles among altricial bird species is mirrored by differing developmental patterns of blood parameters that influence oxygen-carrying capacity (O2Cap). We documented these patterns for the Spotted Turtle-dove (Streptopelia chinensis), which has a growth profile characterised by rapid growth, a short nestling period and asymptotic and fledging masses <60% of adult levels. During nestling development, erythrocyte count (RBC) increased 3.4-fold, and haematocrit (Hct) and blood haemoglobin content (Hb) 1.5-fold. Erythrocyte volume (MCV) decreased from 435 fl to 203 fl. The main mechanism causing the 1.5-fold increase in O2Cap, aRBC increase that more than compensated for the concurrent MCV decrease, resembled that in other altricial birds. At fledging, erythrocyte parameters associated with blood oxygen-carrying capacity were 72–89% of mean adult values. Collectively, the development patterns encompassed features found in both some rapidly and some slowly developing altricial species. For example, Hb increased continuously at a constant rate throughout development, as in some other rapidly growing species, but Hct stopped increasing once a mass of ~74 g had been achieved, a pattern resembling those in some slowly developing species with mass overshoot-recession growth profiles.