Birds are what us science people call a model species – they have been studied for a long time and continue to be studied because there are lots of them and they are relatively easy to study. This amount of research and data collected allows for increased improvement in conservation efforts. However, more research is continuously required due to the massive number of bird species. I would like to share with all of you some of the current research that has been done on Western Meadowlarks (WEME); where “current” in biology means within the last ten years!

As previously mentioned it is recognized that yellow-breasted meadowlarks consist of two species – Western and Eastern. It is the suggestion of Barker et. al. that the Southwestern population of Eastern Meadowlarks, known as Lilian’s Meadowlarks (S. linanae), should be separated and recognized as its own species (2008). This segmenting into three species was proposed after research into mitochondrial and sex-linked genes resulted in historically isolated lineages (Barker et. al. 2008). In biology, the segmentation of species can be evolution in the works; however this reduction in genetic variation can end up being detrimental to the species, in some cases.

A study by Giovanni et. al. in 2011 looked at the effectiveness in detecting Western Meadowlark nests as a way of estimating nest density. They observed adults attending nests and also looked for adults in flight as a result of being flushed from a nest in response to a rope-drag method disturbance (commonly used for grassland bird nests) (Giovanni et. al. 2011). They found that the probability of adults attending nests was 0.46, while the probability of rope dragging provoking a flight response from the adults was 0.19 (Giovanni et. al. 2011). This demonstrated that nest density is subject to detection error and lead to the recommendation for sampling and modeling (computers and math!) to be combined for grassland nest detectability and nest density research (Giovanni et. al. 2011).

With grassland bird populations continuing to decline across North America, Giovanni et. al.  looked at Western Meadowlark fledgling preference and survival relative to age and ambient temperature in an effort to enhance conservation efforts (2015). They found that at high ambient temperatures fledglings preferred locations that had deeper litter with shorter vegetation, whereas younger, nearly flightless, fledglings preferred locations with shallow litter and high vegetation (Giovanni et. al. 2015). Fledgling survival was shown to increase with the ambient temperature and chick age, but decrease as litter depth increased (Giovanni et. al. 2015). Of the 46 fledglings they radio-tracked in 2006/2007, 23 died – 8 from predators (largely by snakes), 2 from haying operations, and 13 from unknown causes (Giovanni et. al. 2015). Although controlled burning would both reduce litter and snake populations – awesome!, it is not a viable conservation strategy in the location of this study –   (the meadows of the Nebraska Sandhills) (Giovanni et. al. 2015). Thus, they recommend late summer harvests to allow time for chicks to fledge (Giovanni et. al. 2015). I agree this strategy should be put forth, although I don’t think it is enough to save our grassland bird species. Yet another reason for more research!

Another study in 2014 looked at the nesting ecology of multiple species, including Western Meadowlark (Ludlow et. al.). It found that predation was the primary cause of nest failure and accounted for 75% of all nest losses (Ludlow et. al. 2014), whereas it accounted for only 35% of fledglings that died in the previously mentioned study (Giovanni et. al. 2015). The study showed that of all species looked at, only Sprague’s Pipit was not parasitized by cowbirds, however few WEME nests were parasitized and of them an average of zero cowbirds fledged (Ludlow et. al. 2014). For those of you whom do not already know about cowbirds, yet another species of blackbird, they don’t fledge their own young. Cowbirds will lay their egg in the nest of another species to be fed and raised until fledging, costly to the host species and nest but very beneficial to the cowbirds – brood parasitism. How awesome are blackbirds?!

Research was done in 2012 on grassland birds in their breeding season during the second and third year after large wildfires (Roberts et. al.). This study was done because fires are a key aspect in maintaining a healthy grassland ecosystem, and was able to vocalize that controlled burns have similar effects on the avian community as the wildfires (Roberts et. al. 2012). It showed that while wildfires were beneficial to some species, for species like WEME that prefer dense vegetation, wildfires have a negative impact on their breeding (Roberts et. al. 2012). However all bird populations seemed to return to pre-burn levels after only three years (Roberts et. al. 2012).

I hope this brief look into how complex ornithology research can be, has been not only informational but enjoyable! And, that I have brought you to the dark side and you have an immense appreciation for blackbirds!

 

References:

Barker, K.F., A.J. Vandergon, and S.M. Lanyon. 2008. Assessment of species limits among yellow-breasted meadowlarks (Sturnella spp.) using mitochondrial and sex-linked markers. The Auk 125(4); 869-879.

Giovanni, M.D., M.P. Van Der Burg, L.C. Anderson, L.A. Powell, W.H. Schacht, and A.J. Tyre. 2011. Estimating nest density when detectability is incomplete: variation in nest attendance and response to disturbance by western meadowlarks. The Condor 113(1): 223-232.

Giovanni, M.D., L.A. Powell, and W.H. Schacht. 2015. Habitat preference and survival for western meadowlark (Sturnella Neglecta) fledglings in a contiguous prairie system. The Wilson Journal of Ornithology 127(2): 200-211.

Ludlow, S.M., R.M. Brigham, and S.K. Davis. 2014. Nesting ecology of grassland songbirds; effects of predation, parasitism and weather. The Wilson Journal of Ornithology 126(4): 686-699.

Roberts, A.J., C.W. Boal, D.B. Wester, S. Rideout-Hanzak, and H.A. Whitlaw. 2012. Grassland bird community response to large wildfires. The Wilson Journal of Ornithology 124(1):24-30.