Sometimes when I take a break from work and walk through a nature path, I listen to a podcast called Zencast which is a collection of hundreds of Dharma talks by dozens of teachers over the decades such as Thich Nhat Hanh and Gil Fronsdal spanning a wide array of topics, such as Five Hindrances, mindfulness, meditation, etc. I highly recommend it, it's a great way to consume teachings on an iPod. When I do this, I am present with body in nature and with mind in enlightened knowledge, but is this technically a technique for a walking meditation?
Yes, in walking meditation we can use any of the 40 objects of meditation.
Listening to Dhamma talks would put it under recollection of the dhamma as it gave you a sense of appreciation of the truth of the dhamma, IMHO,rather than the investigation of Dhamma (Dhammavicaya).
"Mahanama, you should develop this recollection of the Dhamma while you are walking, while you are standing, while you are sitting, while you are lying down, while you are busy at work, while you are resting in your home crowded with children.
I guess it depends on your motivation for meditation. If you are meditating to relax, than your doing a darn good job of it :). However if you are meditating to gain insight, you may or may not be doing so. This is from my own experience of the dharma and I too enjoy Thich Nhat Hanh, as well as Jon Kabat Zinn, Yuttadhammo bhikku etc. I think though, as far as listening to teachers, they can only motivate you to practice. Unfortunately the motivation to practice and the practice itself are definitely two different things. Some research of telepathy suggests that even just listening to teachers can create a connection with them but in the end however, you must walk the path alone. The path includes everything around you though :) and is the most beautiful thing ever! Would you rather be connected to your teachers in that moment your passing wildlife or the beautiful wildlife itself? I'm sure you can answer this one, but remember! enjoying nature comes at a cost, she may ask you to fertilise her once and a while and trim those overgrown hedges! Anyways hope this helps :)