Update

Warm Spring
by Dr. Chip Taylor
March 25, 2017

Journey North

We are experiencing another early spring and it’s no secret that springs are getting earlier and warmer. These changes have consequences and biologists are busy trying to understand the various impacts of early plant growth and higher temperatures on all life forms, from invertebrates to mammals, that might be affected by such changes.

My point of reference for these discussions is the peak bloom of the hundreds of flowering crab apple trees on campus. As a beekeeper for nearly all of my 48 years at the University of Kansas, I have monitored these trees since they are a major source of nectar and pollen for developing honey bee colonies.

The mean date for peak bloom decades ago was the 14th of April. Today, the 25th of March, is the peak day this year - 20 days earlier than the long term average. Early on the peak date would vary a few days to a week from the mean. The variance, mostly, toward early dates, is becoming greater.

So where do monarchs fit in all of this? I just checked the Journey North website and it appears that as of the 21st of March, the returning monarchs this year are:

  1. ahead of the following years: 2016, 2015, 2014, 2010 (the population increased in 2015, 2014, 2010)
  2. similar to: 2013, 2011, 2009, 2008, 2007 (population only increased in 2008)
  3. behind: 2012 - the latter was the hottest March on record (population decreased).

This tells us that being early isn’t necessarily good but we have known that for more than a decade. What this doesn’t tell us is what happens next - specifically when and how many first generation monarchs move north in May and early June.

 
 

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