Effects of environment on invertebrate availability and subsequent effects on growth of Semipalmated Plover (Charadrius semipalmatus ) chicks at Churchill, Manitoba

Avian migrants rely on somewhat predictable patterns of food availability on their breeding grounds to successfully complete their breeding cycle. Due to the ongoing warming of the sub-Arctic, there is potential for a phenological mismatch between the peak in food demand for breeding shorebirds, and the peak in availability of invertebrate biomass. The main objectives of this study were to 1) describe seasonal variation and diversity of invertebrate communities in Churchill, Manitoba, 2) explore relationships between invertebrate biomass and climate variables, 3) assess the temporal synchrony between peak in invertebrate biomass and peak in hatching of Semipalmated Plovers ( Charadrius semipalmatus) in Churchill, Manitoba, and 4) determine if a temporal asynchrony has any impact on the growth of chicks. Invertebrate biomass was found to be greatest approximately one month prior to the hatching of the majority of Semipalmated Plover chicks. A 4-parameter log-logistic curve was fitted to the chick mass at age data, showing much variation between individual chicks. Neither habitat nor the deviation in days between hatch and peak invertebrate biomass explained any of this variation.