Date: 5/31/18 3:45 am
From: Zachary Millen <zjmillen...>
Subject: Night-Heron Hybridization - Lancaster
The well known Ephrata Wellspan hospital night-heron colony has existed for
many years, for a long time hosting only black-crowns to my knowledge. In
2015 a single male yellow-crowned joined them and displayed frequently to
the black-crowns, attempted nest-building, but largely was completely
ignored. Last year he attracted female of his own species and raised at
least two young. This year, however, he again remained alone, displaying
but not nest-building that I saw. In a very interesting turn of events, he
has now persuaded a young female black-crown to begin pair-bonding and
nest-building. I'm not sure on her age, but she appears to be in a subadult
plumage. Average age to sexual maturity is listed as 2-3 years, and they
acquire definitive plumage in their 4th year. The two were observed on
Saturday by me to be working on a partially constructed nest (yellow-crown
doing the work, with female attending), and by Josh Schulz a bit later to
be necking and actually copulating! Yesterday Emily Broich and Laura
Kemmick took more photos which show a pretty complete nest and continued
copulation. It remains to be seen whether they will lay eggs, or even
successfully raise young. However, this hybridization event is so rare in
the wild I thought it would be interesting to share. Successfully hatched
wild hybrid BCNHxYCNH chicks have only been documented in North America
three times from what I can tell: Arizona in 1951, California from 2007 to
maybe 2010, and Colorado in 2011. They will hybridize in captivity when
mates of the same species are not available. An inexperienced female
black-crown and a lonely male yellow-crown are the perfect conditions for
this to occur.

If you come check out these birds, please take photos of their progress and
document any behavior you see to eBird. Enter the hospital parking lot from
Martin Ave and take your first right. They are easily visible in the row of
pines at the back of this lot bordering the houses.

Here are a few photos and notes at our eBird checklists:

Zach Millen
New Holland
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