We are collecting data on chick growth. Chicks are measured every 3 days until they fledge about 21-28 days old. The graph below shows mass gain of chicks at Kap Höegh in 2005 and 2006. Little Auks have a linear period of chick growth (between 5-15 days old), and then reach a peak mass at about 19 days old. Chicks then lose mass before leaving the colony at 21-28 days old.
**Chick Growth of Little Auks in 2005 and 2006 at Kap Hoegh, Greenland **
Little auk weight chart.
Chick growth reflects the amount of food the parents deliver. Chicks may have low linear growth rates, reach a lower peak and fledging mass, and fledge at an older age if food availability is poor. Chicks may also prioritize the growth of some body structures (e.g., wing over leg) if food is in short supply. For each chick we therefore measure the linear growth rates of the leg (tarsus), wing, culmen (bill length), headbill (length of head and bill) and mass. We also measure peak mass, age at peak mass, fledging mass and age at fledging.
We are comparing the growth of chicks measured at Kap Höegh with chicks measured by Nina Karnovsky at Hornsund (see Nina’s Hornsund blogsite) to determine whether differences in chick diet effects chick growth. Although chicks may be fed a diet of different zooplankton species composition and energy value at different sites, parents may be able to compensate for lower prey quality by providing more frequent (or larger) meals. If Little Auk parents have some ability or willingness to increase their provisioning effort then chick growth may not be affected by different prey availability.
pie chart comparison of dietary differences between chicks fed at Hornsund and chicks fed at East Greenland colonies.
Chart comparing the dietary makeup of chicks in Greenland 2004 compared to Homsund 2002.
One week old chick, they grow fast.
One week old chick, they grow fast!