Climate and Chickadees

Black-capped Chickadee

There are a growing number of hybrid cars on New Jersey roads. Hybrids are more commonly known as biological offspring resulting from the interbreeding between two animals or plants of different species.

You might have purchased some hybrid plants at your garden center for planting. Hybrids are deliberately bred to take the best qualities of different species.

But sometimes this breeding occurs "naturally" and perhaps not with good results. Researchers have been studying "hybrid" chickadees. They are the offspring of northern black-capped chickadees and their southern relatives, Carolina chickadees. These two species began to mate in places where their separate ranges now overlap.

You may have learned that if you collected and planted seeds from your hybrid plants that they are infertile. The hybrid chickadees are also infertile and can't reproduce.

They are found only in a long, narrow strip of territory stretching from Kansas to New Jersey.

I first learned about this zone and the hybrid birds in a post by Michele S. Byers, Executive Director of the New Jersey Conservation Foundation.


The "hybrid zone" is a shifting line and the researchers have discovered it is a fairly accurate way of measuring the progression of global temperature changes.

The has moved north at a rate of about seven miles over the last 10 years. This matches the warming trend in winter temperatures.

In New Jersey, the hybrid zone crosses from Trenton to the Raritan Bay - the southern edge of the Piedmont region.

Carolina chickadee

It always seems to be controversial to bring up climate change, but it may be facilitating the northward movement of this zone. We know that looking at the minimum winter temperature in an area is a way to accurately predict the location of the hybrid zone, and minimum winter temperatures have gone up over the past decade.

Hybrid chickadees can be hard to distinguish by sight, so blood samples are used. The hybrid songs are a mix of the distinctive songs of the parent species.

The hybrid chickadee can eat a wide variety of foods. If one food source disappears, they find another. But about 75% of animals and plants have little or no ability to move as the climate warms.

You might guess that all birds could easily adapt by flying to new places, but that's not the case. Rather than being "generalists", like the chickadee, many birds, butterflies and moths are "specialists," adapted over millennia to depend on specific food sources. If the food sources decline as the climate changes, populations of these species will diminish or disappear.

Changes in our climate is happening too fast for most species to adapt. Habitats also have to adapt but some sensitive habitat have plants that cannot adapt and so will simply collapse and disappear.

The hybrid chickadees may be like the "canary in a coalmine"providing an indicator and a warning of changes in the environment.

Disappearing and Reappearing Butterflies

Florida's Meske's skipper was gone for a decade before returning.Photo: Mary Keimat/Flickr
A story from Florida makes it clear how unclear the status of a species can be when it comes to government listings.

If a species was never listed as threatened or endangered, but it appears to be extirpated or even extinct, it falls into a odd gray area. The government won’t declare them extinct. Technically, if we keep a species off the endangered species list, then it can’t go extinct.

The rockland Meske’s skipper appeared to be gone for good but the state government didn't want to declare them extinct. Then, it was seen again.

The species in Florida include two that have endangered status and two (the Florida leafwing and Bartram’s scrub-hairstreak) have been elevated to “candidates.” The agency won’t add something just to turn around and stamp it extinct.
Source: Mother Jones "5 Butterfly Species Just Vanished While No One Was Looking"

Climate and Hardiness Zones in NJ

planting early lettuce

Hardiness Zones, Gardening Zones, Growing Zones and Plant Zones refer to defined geographic regions that can support specific plants, flowers and trees.

The zones define a minimum range of temperatures that a plant or tree can survive safely in that zone.

The most common are the Hardiness Zones defined by the U.S. Department of Agriculture (USDA).

In 2012 the USDA released an updated New Jersey hardiness zone map covering the period of 1981-2010. Believe what you will about climate change, but the trees are blooming earlier the past few decades.

warm weather planting - tomatoes

New Jersey's plant hardiness zone was changed in 2011 based on the warmer winters.

In 2012, trees started blooming around March 5. In 2010, after a warm spell at the end of March, the trees bloomed by April 1st.

For my part of NJ, we are in Zone 6B. The average first frost is between October 11 - 20 and the average last frost is April 11 - 20.

Hackensack’s Borg’s Woods and Wawayanda Swamp Natural Area

The improving weather makes many of us more enthusiastic about getting out for a walk or hike. Looking through the many options at NJ Urban Forest, I came upon two North Jersey possibilities for this weekend.

Both of these rambles go through areas that were once commercially owned and that were obtained for preservation and recreation.

First up is Hackensack’s Borg’s Woods. About 14 acres of Borg’s Woods were originally owned by Macromedia, Inc., which planned to build a condominium development in the mid-1980s. After years of legal battles, Bergen County purchased the parcel in 1994, and an additional acre of the Summit Hill Ridge was purchased from two homeowners by the County in 1995.

Of course, these urban forests - as the name suggests - have pretty mild and shorter "hikes" that serious hikers would consider more of a walk.

The second trek goes through a section of Wawayanda State Park. The park was one of the first major acquisitions by the New Jersey Green Acres program in 1963 from the New Jersey Zinc Company.

“Wawayanda” is like many NJ locations of Lenape Indian origin. The word is said to mean "water on the mountain," although in modern parlance, some say it means “way way yonder” since the park is rather remotely located in northwestern Passaic and southeastern Sussex counties.

The hike offered takes you to a rare inland Atlantic White Cedar swamp in the 2,167-acre park. The Wawayanda Swamp Natural Area is the largest natural area in the park.