Marine vertebrates show a diversity of migration strategies, including sex differences. This may lead to differential demography, but the consequences of such between-sex variation are little understood. Here, we studied the migration of known-sex northern gannets Morus bassanus—a partial migrant with females ~8% heavier than males. We used geolocators to determine wintering areas of 49 breeding adults (19 females and 30 males during 2010 to 2014) from 2 colonies in the northeast Atlantic (Bass Rock and Grassholm, UK). We also tested for sex-specific survival probabilities using capture-mark-recapture methods (n = 72 individuals Bass Rock, n = 229 individuals Grassholm; 2010-2018) and applied sex-specific population projection matrices (PPMs) to quantify population-level effects. Tracked gannets wintered in a range of large marine ecosystems (LMEs): Canary Current LME (CCLME; 69%), Celtic-Biscay Shelf LME (16%), Iberian Coastal LME (8%), North Sea LME (4%) or Mediterranean LME (2%). Migratory destination differed between the sexes: 90% of females vs. 57% of males wintered in the CCLME. Survival was similar between the sexes at Bass Rock (mean ± 95% CI = 0.951 ± 0.053 and 0.956 ± 0.047 for females and males, respectively). At Grassholm, there was evidence of slight sex differences in breeder survival: females had lower annual survival (0.882 ± 0.040) than males (0.946 ± 0.026). At Bass Rock, PPMs with no sex effect best fitted the observed population increase (1994-2014). Sex-specific PPMs fitted the population estimates for Grassholm (1995-2015). Our results reveal that female gannets are more likely to travel further than males to winter in the CCLME. This difference is unlikely due to morphological differences, unlike in other bird species. However, the reason for slightly higher over-winter female mortality at Grassholm is unclear.
ShareShareSharePrintMailGooglePinterestDiggRedditStumbleuponDeliciousBufferTumblr Last year we had the fervor of Apple Pay launching in the financial services industry. This year we have round two of buzzing anticipation of the launch of both Android Pay and Samsung Pay solutions — just in time for the holidays. And in the thick of it is, of course, The Members Group whose credit union clients experienced the Apple Pay tidal wave last year with 75% of their clients using the solution. Now they get to add yet another couple of options with Android and Samsung. continue reading »
Christopher Katongo feels the pressure the Bafana Bafana players will be under to impress Gordon Igesund might play to Zambia’s advantage when they clash in the Nelson Mandela Challenge.Chipolopolo are in town to face South Africa at the FNB Stadium on Wednesday, and skipper Katongo believes that Igesund’s players have a lot to prove to their coach ahead of the 2013 Africa Cup of Nations.Katongo explained to Football411: “It is a new team with Pitso (Mosimane) gone and all these players want to prove themselves to the coach so they can have a place in the AFCON squad.“So it is not gonna be easy for them, but as for us we have the same players and nothing has been changed so we know each other. We don’t have pressure,” he added.Kick-off for Wednesday’s clash is 20:00 at Soccer City in Johannesburg.