Dear Colleagues, My coauthors and I are excited to share our new publication using 40 years of data to examine the contributions of population density, maternal effects, and ocean conditions to weaning mass in the northern elephant seal. This article is open access and can be found here: https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1258 - Holser Rachel R. <https://royalsocietypublishing.org/author/Holser%2C+Rachel+R>, - Crocker Daniel E. <https://royalsocietypublishing.org/author/Crocker%2C+Daniel+E>, - Robinson Patrick W. <https://royalsocietypublishing.org/author/Robinson%2C+Patrick+W>, - Condit Richard <https://royalsocietypublishing.org/author/Condit%2C+Richard> and - Costa Daniel P. <https://royalsocietypublishing.org/author/Costa%2C+Daniel+P> 2021Density-dependent effects on reproductive output in a capital breeding carnivore, the northern elephant seal (*Mirounga angustirostris*) Proc. R. Soc. B.288 20211258 Abstract: All organisms face resource limitations that will ultimately restrict population growth, but the controlling mechanisms vary across ecosystems, taxa, and reproductive strategies. Using four decades of data, we examine how variation in the environment and population density affect reproductive outcomes in a capital-breeding carnivore, the northern elephant seal (*Mirounga angustirostris*). This species provides a unique opportunity to examine the relative importance of resource acquisition and density-dependence on breeding success. Capital breeders accrue resources over large temporal and spatial scales for use during an abbreviated reproductive period. This strategy may have evolved, in part, to confer resilience to short-term environmental variability. We observed density-dependent effects on weaning mass, and maternal age (experience) was more important than oceanographic conditions or maternal mass in determining offspring weaning mass. Together these findings show that the mechanisms controlling reproductive output are conserved across terrestrial and marine systems and vary with population dynamics, an important consideration when assessing the effect of extrinsic changes, such as climate change, on a population. Feel free to contact me at rholser@ucsc.edu if you have any questions. All the best, Rachel Holser -- Rachel Holser, Ph.D. Postdoctoral Researcher Institute of Marine Sciences University of California, Santa Cruz 115 McAllister Way Santa Cruz, CA 95060