220
11. Horseshoe Crabs and Shorebirds
JUVYEARS
EGGS INTO CRABS
JUVDEATH
FIGURE 11.2
The bird population modu le (Figure 11.4) is based on estimates of the
total amo unt of birds using the Delaware Bay as a stopover site, for a period of two months. The population of birds returns to the bay each year,
fluctuating as a function of the number of eggs each bird receives and their
ove rall fitness level. Since one bird hatche s from every clutch of eggs a female lays when she is completely "fit," the existing stock is fully replenished the next season. It is assumed that consuming 135,000 eggs will double each bird's body mass, pro viding sufficient energy to complete its
migration . If each female does not double her bod y mass, then he r fitness
PROMOTlON
ADULTCRABS
NATURAL DEATH
STlRANDING
CONCH RATE
STlRANDINGRATE
EELRATE
FIGURE 11.3
11. Horseshoe Crabs and Shorebirds
JUVYEARS
EGGS INTO CRABS
JUVDEATH
FIGURE 11.2
The bird population modu le (Figure 11.4) is based on estimates of the
total amo unt of birds using the Delaware Bay as a stopover site, for a period of two months. The population of birds returns to the bay each year,
fluctuating as a function of the number of eggs each bird receives and their
ove rall fitness level. Since one bird hatche s from every clutch of eggs a female lays when she is completely "fit," the existing stock is fully replenished the next season. It is assumed that consuming 135,000 eggs will double each bird's body mass, pro viding sufficient energy to complete its
migration . If each female does not double her bod y mass, then he r fitness
PROMOTlON
ADULTCRABS
NATURAL DEATH
STlRANDING
CONCH RATE
STlRANDINGRATE
EELRATE
FIGURE 11.3