Do female pumas (Puma concolor) exhibit a birth pulse?

Female pumas (Puma concolor) give birth in all months of the year with a possible birth pulse in July-September. This pulse is proposed to be timed to provide increased survival probabilities to young born during these months. We tested data on birth dates from 8 different studies for a birth pulse. We also compared survival rates for young born in July-September to those for young born outside of these dates during a 17-year study in Idaho and Utah. The distribution of litters born per month was not unifonn, with 41% of births occurring in July-September. Survival rates of young born in July-September were equal to those in other months of the year (0.774 +/- 0.006 versus 0.779 +/- 0.004). We conclude that there was a propensity for higher numbers of litters to be born in July-September. However, we rejected the hypothesis that young born in July-September had greater survival than young born at other times of the year. We suggest that rather than there being a survival advantage to pumas born in July-September, perhaps there is a survival disadvantage to those born in January-February (4.5% of 484 litters). However, there were insufficient data to test this alternate hypothesis.