Russell A. Charif

Spatial relationships and matrilineal kinship in African savanna elephant (Loxodonta africana) clans

African savanna elephants, Loxodonta africana, live in stable family groups consisting of adult females and their dependent offspring. During the dry season, “clans” consisting of several family groups typically share a common home range. We compared spatial relationships and mitochondrial DNA (mtDNA) haplotypes among 14 adult female elephants within 3 clans during the dry season in northern Zimbabwe. Spatial relationships were studied by radio-tracking. Home-range similarity was quantified by correlating the estimated utilization distributions of all pairs of elephants. Clans were identified by cluster analysis of the home-range similarity values. All three clans contained at least two of the five mtDNA haplotypes that were found, indicating that clan members are not necessarily matrilineally related. Within clans, home ranges of elephants with the same haplotype were not significantly more similar to each other than those of elephants with different haplotypes. Most elephants within each clan used their shared home ranges independently of each other: the distribution of distances between their positions at any given time did not differ from the distribution expected by chance. However, 8 out of the 26 within-clan pairs exhibited long-term coordination of space use by remaining within known hearing distance of each other’s low-frequency calls significantly more often than expected by chance. At least four of these coordinated pairs consisted of animals in different family groups. Elephants in three of the four different-family pairs whose movements were coordinated had different haplotypes. Further research is needed to determine the relationship between these coordinated movements and conventionally defined bond-group behavior.

Bowhead whale acoustic activity in the southeast Beaufort Sea during late summer 2008–2010

Autonomous passive acoustic recorders were deployed to record sounds of bowhead whales (Balaena mysticetus) in the southeast Beaufort Sea for periods of 30-55 days during the late summer, open-water seasons of 2008-2010. Recordings were made in three areas licensed for hydrocarbon exploration, spanning the continental slope and adjacent outer shelf, and in a shallow inner-shelf area where bowheads have been observed congregating to feed in recent decades. Bowhead sounds were counted in samples comprising 10% of each recorded hour. In mid-August and September in all 3 years, the rate of bowhead calling at outer shelf sites exceeded that at adjacent continental slope sites by one to two orders of magnitude. Higher rates of calling occurred on the slope in late July and early August than at later dates. Calling rates varied by an order of magnitude between years in the one area that was monitored in different years. The highest rates of calling occurred on the inner shelf, offshore of the northern Tuktoyaktuk Peninsula. These trends are consistent with patterns of habitat use previously reported from aerial surveys in this and nearby areas of the Beaufort Sea and with the results of satellite tagging studies.

Long-term passive acoustic recordings track the changing distribution of North Atlantic right whales (Eubalaena glacialis) from 2004 to 2014

Given new distribution patterns of the endangered North Atlantic right whale (NARW; Eubalaena glacialis) population in recent years, an improved understanding of spatio-temporal movements are imperative for the conservation of this species. While so far visual data have provided most information on NARW movements, passive acoustic monitoring (PAM) was used in this study in order to better capture year-round NARW presence. This project used PAM data from 2004 to 2014 collected by 19 organizations throughout the western North Atlantic Ocean. Overall, data from 324 recorders (35,600 days) were processed and analyzed using a classification and detection system. Results highlight almost year-round habitat use of the western North Atlantic Ocean, with a decrease in detections in waters off Cape Hatteras, North Carolina in summer and fall. Data collected post 2010 showed an increased NARW presence in the mid-Atlantic region and a simultaneous decrease in the northern Gulf of Maine. In addition, NARWs were widely distributed across most regions throughout winter months. This study demonstrates that a large-scale analysis of PAM data provides significant value to understanding and tracking shifts in large whale movements over long time scales.

Results and insights from operational acoustic monitoring networks in the Chukchi Sea, Summer‐Fall 2006 and 2008.

Recordings for marine mammals were collected in the Chukchi Sea in the 2006 and 2008 summer‐fall seasons in proximity to seismic exploration activities. 2006 data were from MARUs off Cape Lisburne, Pt. Lay, Wainwright, and Pt. Barrow, AK. 2008 data were from MARUs in the Burger and Klondike areas. In 2006, belugas, but no bowheads, were rarely detected off Cape Lisburne in July–September. Bowheads, but no belugas, were detected off Wainwright, Lay, and Barrow in September–October, with bowheads very common off Barrow. Seismic airgun sounds were common on distant MARUs off Cape Lisburne, Lay, and Wainwright. There were very few seismic events detected off Barrow and those few were all close to 0‐dB SNR. In 2008, bowheads were more common at Burger than Klondike and occurred mostly during the latter part of the September–October period; belugas were not detected at Burger and only on 6 days early in the period at Klondike; walrus were more common at Burger than at Klondike. In both areas bowhead densities w...

Evidence for vocal performance constraints in a female nonhuman primate

Trilled vocalizations, wherein notes are repeated in rapid succession, are found in a variety of taxa including oscine birds, singing mice and nonhuman primates. Previous work on birds and singing mice has provided evidence of vocal performance constraints in trills, where there is a trade-off between the rate of the note repetition and the bandwidth (or frequency range) of each note. Here, we investigate vocal performance constraints in the trilled portion of the female contribution to the duet in the Bornean gibbon, Hylobates muelleri, recorded from seven sites in Sabah, Malaysia. We used two approaches. First, to ensure that our results were comparable with previous studies on vocal performance constraints, we used a 90% quantile regression to examine the relationship between trill rate and bandwidth. We found that there was a significant negative correlation between bandwidth and trill rate. Second, we formally compared multiple hierarchical models to identify the best predictors of bandwidth and trill rate. Our top model predicting bandwidth showed that trill rate and location within the trill were reliable predictors of bandwidth. With trill rate as the response variable, our top model included location within the trill as well as trill duration. We found that there were no important site-level differences in bandwidth but that trill rate varied predictably among sites. Our analyses provide strong evidence for performance constraints in the production of trills in Bornean gibbon females. Further research is needed to determine whether higher-performance trills provide honest signals of caller quality and whether gibbons respond differently to low- and high-performance calls.